diff --git a/src/ape/api/config.py b/src/ape/api/config.py
index 0c2e5cbd7a..e22a383b59 100644
--- a/src/ape/api/config.py
+++ b/src/ape/api/config.py
@@ -402,10 +402,10 @@ def write_to_disk(self, destination: Path, replace: bool = False):
                 yaml.safe_dump(data, file)
 
         elif destination.suffix == ".json":
-            destination.write_text(self.model_dump_json(by_alias=True))
+            destination.write_text(self.model_dump_json(by_alias=True), encoding="utf8")
 
         else:
-            raise ValueError(f"Unsupported destination file type {destination}.")
+            raise ConfigError(f"Unsupported destination file type '{destination}'.")
 
 
 def _get_compile_configs_from_manifest(manifest: PackageManifest) -> dict[str, dict]:
diff --git a/src/ape/managers/chain.py b/src/ape/managers/chain.py
index 2324b7179c..836dc88385 100644
--- a/src/ape/managers/chain.py
+++ b/src/ape/managers/chain.py
@@ -1345,22 +1345,22 @@ def _get_contract_creation_from_disk(self, address: AddressType) -> Optional[Con
     def _cache_contract_to_disk(self, address: AddressType, contract_type: ContractType):
         self._contract_types_cache.mkdir(exist_ok=True, parents=True)
         address_file = self._contract_types_cache / f"{address}.json"
-        address_file.write_text(contract_type.model_dump_json())
+        address_file.write_text(contract_type.model_dump_json(), encoding="utf8")
 
     def _cache_proxy_info_to_disk(self, address: AddressType, proxy_info: ProxyInfoAPI):
         self._proxy_info_cache.mkdir(exist_ok=True, parents=True)
         address_file = self._proxy_info_cache / f"{address}.json"
-        address_file.write_text(proxy_info.model_dump_json())
+        address_file.write_text(proxy_info.model_dump_json(), encoding="utf8")
 
     def _cache_blueprint_to_disk(self, blueprint_id: str, contract_type: ContractType):
         self._blueprint_cache.mkdir(exist_ok=True, parents=True)
         blueprint_file = self._blueprint_cache / f"{blueprint_id}.json"
-        blueprint_file.write_text(contract_type.model_dump_json())
+        blueprint_file.write_text(contract_type.model_dump_json(), encoding="utf8")
 
     def _cache_contract_creation_to_disk(self, address: AddressType, creation: ContractCreation):
         self._contract_creation_cache.mkdir(exist_ok=True, parents=True)
         path = self._contract_creation_cache / f"{address}.json"
-        path.write_text(creation.model_dump_json())
+        path.write_text(creation.model_dump_json(), encoding="utf8")
 
     def _load_deployments_cache(self) -> dict:
         return (
diff --git a/src/ape/managers/project.py b/src/ape/managers/project.py
index 26f4ab15ca..5eff5360cc 100644
--- a/src/ape/managers/project.py
+++ b/src/ape/managers/project.py
@@ -883,7 +883,7 @@ def cache_api(self, api: DependencyAPI) -> Path:
             exclude_defaults=True,
         )
 
-        api_file.write_text(json_text)
+        api_file.write_text(json_text, encoding="utf8")
         return api_file
 
     def remove(self, package_id: str, version: str):
@@ -1605,7 +1605,7 @@ def unpack(self, destination: Path, config_override: Optional[dict] = None) -> "
         for source_id, src in sources.items():
             path = destination / source_id
             path.parent.mkdir(parents=True, exist_ok=True)
-            path.write_text(str(src.content))
+            path.write_text(str(src.content), encoding="utf8")
 
         # Unpack config file.
         self.config.write_to_disk(destination / "ape-config.yaml")
@@ -1899,7 +1899,7 @@ def track(self, contract: ContractInstance):
             # NOTE: missing_ok=True to handle race condition.
             destination.unlink(missing_ok=True)
 
-        destination.write_text(artifact.model_dump_json())
+        destination.write_text(artifact.model_dump_json(), encoding="utf8")
 
     def __iter__(self) -> Iterator[EthPMContractInstance]:
         """
@@ -2318,7 +2318,7 @@ def update_manifest(self, **kwargs):
         self.manifest_path.unlink(missing_ok=True)
         manifest_text = self.manifest.model_dump_json(mode="json", by_alias=True)
         self.manifest_path.parent.mkdir(parents=True, exist_ok=True)
-        self.manifest_path.write_text(manifest_text)
+        self.manifest_path.write_text(manifest_text, encoding="utf8")
 
     def load_contracts(
         self, *source_ids: Union[str, Path], use_cache: bool = True
@@ -2414,7 +2414,7 @@ def _update_contract_types(self, contract_types: dict[str, ContractType]):
                 abi_json = json.dumps(
                     [x.model_dump_json(by_alias=True, mode="json") for x in ct.abi]
                 )
-                file.write_text(abi_json)
+                file.write_text(abi_json, encoding="utf8")
 
 
 def _find_directory_with_extension(
diff --git a/src/ape/types/coverage.py b/src/ape/types/coverage.py
index f343b04c93..760d20935a 100644
--- a/src/ape/types/coverage.py
+++ b/src/ape/types/coverage.py
@@ -812,7 +812,7 @@ def write_xml(self, path: Path):
             path = path / "coverage.xml"
 
         path.unlink(missing_ok=True)
-        path.write_text(xml)
+        path.write_text(xml, encoding="utf8")
 
     def write_html(self, path: Path, verbose: bool = False):
         if not (html := self.get_html(verbose=verbose)):
@@ -833,7 +833,7 @@ def write_html(self, path: Path, verbose: bool = False):
         # Create new index.html.
         index = html_path / "index.html"
         index.unlink(missing_ok=True)
-        index.write_text(html)
+        index.write_text(html, encoding="utf8")
 
         favicon = html_path / "favicon.ico"
         if not favicon.is_file():
@@ -862,7 +862,7 @@ def write_html(self, path: Path, verbose: bool = False):
 
             css = html_path / "styles.css"
             css.unlink(missing_ok=True)
-            css.write_text(_CSS)
+            css.write_text(_CSS, encoding="utf8")
 
     def get_html(self, verbose: bool = False) -> str:
         """
diff --git a/src/ape_accounts/accounts.py b/src/ape_accounts/accounts.py
index 60ec34d371..d4ab603534 100644
--- a/src/ape_accounts/accounts.py
+++ b/src/ape_accounts/accounts.py
@@ -115,7 +115,7 @@ def public_key(self) -> HexBytes:
         key_file_data = self.keyfile
         key_file_data["public_key"] = publicKey[2:]
 
-        self.keyfile_path.write_text(json.dumps(key_file_data))
+        self.keyfile_path.write_text(json.dumps(key_file_data), encoding="utf8")
 
         return HexBytes(bytes.fromhex(publicKey[2:]))
 
@@ -148,7 +148,9 @@ def change_password(self):
         key = self.__key
 
         passphrase = self._prompt_for_passphrase("Create new passphrase", confirmation_prompt=True)
-        self.keyfile_path.write_text(json.dumps(EthAccount.encrypt(key, passphrase)))
+        self.keyfile_path.write_text(
+            json.dumps(EthAccount.encrypt(key, passphrase)), encoding="utf8"
+        )
 
     def delete(self):
         passphrase = self._prompt_for_passphrase(
@@ -293,7 +295,7 @@ def _write_and_return_account(alias: str, passphrase: str, account: LocalAccount
     path = ManagerAccessMixin.account_manager.containers["accounts"].data_folder.joinpath(
         f"{alias}.json"
     )
-    path.write_text(json.dumps(EthAccount.encrypt(account.key, passphrase)))
+    path.write_text(json.dumps(EthAccount.encrypt(account.key, passphrase)), encoding="utf8")
 
     return KeyfileAccount(keyfile_path=path)
 
diff --git a/src/ape_init/_cli.py b/src/ape_init/_cli.py
index dd2000b3eb..1d6fcd6673 100644
--- a/src/ape_init/_cli.py
+++ b/src/ape_init/_cli.py
@@ -71,12 +71,12 @@ def cli(cli_ctx, github):
             cli_ctx.logger.warning(f"Unable to create .gitignore: '{git_ignore_path}' file exists.")
         else:
             git_ignore_path.touch()
-            git_ignore_path.write_text(GITIGNORE_CONTENT.lstrip())
+            git_ignore_path.write_text(GITIGNORE_CONTENT.lstrip(), encoding="utf8")
 
         ape_config = project_folder / CONFIG_FILE_NAME
         if ape_config.exists():
             cli_ctx.logger.warning(f"'{ape_config}' exists")
         else:
             project_name = click.prompt("Please enter project name")
-            ape_config.write_text(f"name: {project_name}\n")
+            ape_config.write_text(f"name: {project_name}\n", encoding="utf8")
             cli_ctx.logger.success(f"{project_name} is written in {CONFIG_FILE_NAME}")
diff --git a/src/ape_pm/dependency.py b/src/ape_pm/dependency.py
index 892ad48b41..d7d0bfe94c 100644
--- a/src/ape_pm/dependency.py
+++ b/src/ape_pm/dependency.py
@@ -85,7 +85,7 @@ def fetch(self, destination: Path):
 
             destination.unlink(missing_ok=True)
             destination.parent.mkdir(parents=True, exist_ok=True)
-            destination.write_text(self.local.read_text())
+            destination.write_text(self.local.read_text(), encoding="utf8")
 
 
 class GithubDependency(DependencyAPI):
diff --git a/tests/conftest.py b/tests/conftest.py
index 55b278288f..980f924f65 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -356,7 +356,7 @@ def _make_keyfile_account(base_path: Path, alias: str, params: dict, funder):
         # Corrupted from a previous test
         test_keyfile_path.unlink()
 
-    test_keyfile_path.write_text(json.dumps(params))
+    test_keyfile_path.write_text(json.dumps(params), encoding="utf8")
     acct = ape.accounts.load(alias)
     funder.transfer(acct, "25 ETH")  # Auto-fund this account
     return acct
diff --git a/tests/functional/test_cli.py b/tests/functional/test_cli.py
index 4820204e05..0867b11885 100644
--- a/tests/functional/test_cli.py
+++ b/tests/functional/test_cli.py
@@ -486,7 +486,7 @@ def test_contract_file_paths_argument_handles_exclude(
     # make a .cache file to show it is ignored.
     cache_file = project_with_contract.contracts_folder / ".cache" / "thing.json"
     cache_file.parent.mkdir(parents=True, exist_ok=True)
-    cache_file.write_text("FAILS IF LOADED")
+    cache_file.write_text("FAILS IF LOADED", encoding="utf8")
 
     result = runner.invoke(contracts_paths_cmd, "contracts")
     assert "Exclude.json" not in result.output
diff --git a/tests/functional/test_compilers.py b/tests/functional/test_compilers.py
index 26c718a08b..92542d5f24 100644
--- a/tests/functional/test_compilers.py
+++ b/tests/functional/test_compilers.py
@@ -85,7 +85,7 @@ def test_contract_type_collision(compilers, project_with_contract, mock_compiler
         new_contract = project_with_contract.path / existing_contract.source_id.replace(
             ".json", mock_compiler.ext
         )
-        new_contract.write_text("foobar")
+        new_contract.write_text("foobar", encoding="utf8")
         to_compile = [existing_path, new_contract]
         compile = compilers.compile(to_compile, project=project_with_contract)
 
@@ -100,7 +100,7 @@ def test_contract_type_collision(compilers, project_with_contract, mock_compiler
 
 def test_compile_with_settings(mock_compiler, compilers, project_with_contract):
     new_contract = project_with_contract.path / f"AMockContract{mock_compiler.ext}"
-    new_contract.write_text("foobar")
+    new_contract.write_text("foobar", encoding="utf8")
     settings = {"mock": {"foo": "bar"}}
 
     _ = compilers.registered_compilers  # Ensures cached property is set.
diff --git a/tests/functional/test_config.py b/tests/functional/test_config.py
index 1e9e76111c..31041c281f 100644
--- a/tests/functional/test_config.py
+++ b/tests/functional/test_config.py
@@ -8,6 +8,7 @@
 from ape.exceptions import ConfigError
 from ape.managers.config import CONFIG_FILE_NAME, merge_configs
 from ape.types import GasLimit
+from ape.utils import create_tempdir
 from ape_ethereum.ecosystem import EthereumConfig, NetworkConfig
 from ape_networks import CustomNetwork
 from tests.functional.conftest import PROJECT_WITH_LONG_CONTRACTS_FOLDER
@@ -219,7 +220,7 @@ def test_global_config(data_folder, config):
 test:
   number_of_accounts: 11
 """.strip()
-    config_file.write_text(config_content)
+    config_file.write_text(config_content, encoding="utf8")
     global_config = config.load_global_config()
     assert global_config.get_config("test").number_of_accounts == 11
     config_file.unlink(missing_ok=True)
@@ -346,3 +347,24 @@ def hacked_in_method():
 
     finally:
         config.local_project.config._get_config_plugin_classes = original_method
+
+
+def test_write_to_disk_json(config):
+    with create_tempdir() as base_path:
+        path = base_path / "config.json"
+        config.write_to_disk(path)
+        assert path.is_file()
+
+
+def test_write_to_disk_yaml(config):
+    with create_tempdir() as base_path:
+        path = base_path / "config.yaml"
+        config.write_to_disk(path)
+        assert path.is_file()
+
+
+def test_write_to_disk_txt(config):
+    with create_tempdir() as base_path:
+        path = base_path / "config.txt"
+        with pytest.raises(ConfigError, match=f"Unsupported destination file type '{path}'."):
+            config.write_to_disk(path)
diff --git a/tests/functional/test_coverage.py b/tests/functional/test_coverage.py
index 00a3fcdd18..bba0684227 100644
--- a/tests/functional/test_coverage.py
+++ b/tests/functional/test_coverage.py
@@ -247,7 +247,7 @@ def init_profile(source_cov, src):
             # Create a source file.
             file = tmp.path / "contracts" / filename
             file.parent.mkdir(exist_ok=True, parents=True)
-            file.write_text("testing")
+            file.write_text("testing", encoding="utf8")
 
             # Ensure the TB refers to this source.
             tb_data["source_path"] = f"{tmp.path}/contracts/{filename}"
diff --git a/tests/functional/test_dependencies.py b/tests/functional/test_dependencies.py
index c5f51e8628..80c0d08e70 100644
--- a/tests/functional/test_dependencies.py
+++ b/tests/functional/test_dependencies.py
@@ -40,14 +40,14 @@ def project_with_downloaded_dependencies(project, oz_dependencies_config):
         manifest_source = oz_manifests / version / "openzeppelin.json"
         manifest_dest = oz_manifests_dest / f"{version.replace('.', '_')}.json"
         manifest_dest.unlink(missing_ok=True)
-        manifest_dest.write_text(manifest_source.read_text())
+        manifest_dest.write_text(manifest_source.read_text(), encoding="utf8")
 
         # Also, copy in the API data
         api_dest = base.api_folder / package_id / f"{version.replace('.', '_')}.json"
         api_dest.unlink(missing_ok=True)
         cfg = [x for x in oz_dependencies_config["dependencies"] if x["version"] == version][0]
         api_dest.parent.mkdir(exist_ok=True, parents=True)
-        api_dest.write_text(json.dumps(cfg))
+        api_dest.write_text(json.dumps(cfg), encoding="utf8")
 
     with project.temp_config(**oz_dependencies_config):
         yield project
@@ -125,7 +125,7 @@ def test_decode_dependency_with_config_override(project):
         base_path = tmp_project.path / path
         contracts_path = base_path / "contracts"
         contracts_path.mkdir(parents=True, exist_ok=True)
-        (contracts_path / "contract.json").write_text('{"abi": []}')
+        (contracts_path / "contract.json").write_text('{"abi": []}', encoding="utf8")
 
         data = {"name": "FooBar", "local": path, "config_override": settings}
         dependency = tmp_project.dependencies.decode_dependency(**data)
@@ -186,7 +186,7 @@ def test_add(project):
     with project.isolate_in_tempdir() as tmp_project:
         contracts_path = tmp_project.path / "src"
         contracts_path.mkdir(exist_ok=True, parents=True)
-        (contracts_path / "contract.json").write_text('{"abi": []}')
+        (contracts_path / "contract.json").write_text('{"abi": []}', encoding="utf8")
         data = {"name": "FooBar", "local": f"{tmp_project.path}"}
 
         dependency = project.dependencies.add(data)
@@ -217,7 +217,7 @@ def test_install(project, mocker):
     with project.isolate_in_tempdir() as tmp_project:
         contracts_path = tmp_project.path / "src"
         contracts_path.mkdir(exist_ok=True, parents=True)
-        (contracts_path / "contract.json").write_text('{"abi": []}')
+        (contracts_path / "contract.json").write_text('{"abi": []}', encoding="utf8")
         data = {"name": "FooBar", "local": f"{tmp_project.path}"}
         get_spec_spy = mocker.spy(tmp_project.dependencies, "_get_specified")
         install_dep_spy = mocker.spy(tmp_project.dependencies, "install_dependency")
@@ -369,10 +369,10 @@ def node_modules_path(self, project_with_npm_dependency, request, mock_home_dire
         contracts_folder = package_folder / "contracts"
         contracts_folder.mkdir(parents=True)
         package_json = package_folder / "package.json"
-        package_json.write_text(f'{{"version": "{self.VERSION}"}}')
+        package_json.write_text(f'{{"version": "{self.VERSION}"}}', encoding="utf8")
         file = contracts_folder / "contract.json"
         source_content = '{"abi": []}'
-        file.write_text(source_content)
+        file.write_text(source_content, encoding="utf8")
         yield base
 
     def test_fetch(self, node_modules_path, project_with_npm_dependency):
@@ -582,7 +582,7 @@ def test_load_contracts_with_config_override(self, project):
             override = {"contracts_folder": "src"}
             contracts_path = tmp_project.path / "src"
             contracts_path.mkdir(exist_ok=True, parents=True)
-            (contracts_path / "contract.json").write_text('{"abi": []}')
+            (contracts_path / "contract.json").write_text('{"abi": []}', encoding="utf8")
 
             # use_cache=False only to lessen stateful test clobbering.
             data = {
diff --git a/tests/functional/test_project.py b/tests/functional/test_project.py
index de42887727..79ae7d44f8 100644
--- a/tests/functional/test_project.py
+++ b/tests/functional/test_project.py
@@ -132,7 +132,7 @@ def test_contracts_folder_deduced(tmp_project):
     contracts_folder.mkdir()
     contract = contracts_folder / "tryme.json"
     abi = [{"name": "foo", "type": "fallback", "stateMutability": "nonpayable"}]
-    contract.write_text(json.dumps(abi))
+    contract.write_text(json.dumps(abi), encoding="utf8")
     new_project = Project(new_project_path)
     actual = new_project.contracts_folder
     assert actual == contracts_folder
@@ -180,7 +180,7 @@ def test_getattr_detects_changes(tmp_project):
     path = tmp_project.sources.lookup(source_id)
     assert path
     path.unlink(missing_ok=True)
-    path.write_text(content)
+    path.write_text(content, encoding="utf8")
     # Should have re-compiled.
     contract = tmp_project.Other
     assert "retrieve" in contract.contract_type.methods
@@ -193,7 +193,7 @@ def test_getattr_empty_contract(tmp_project):
     source_id = tmp_project.Other.contract_type.source_id
     path = tmp_project.sources.lookup(source_id)
     path.unlink(missing_ok=True)
-    path.write_text("")
+    path.write_text("", encoding="utf8")
     # Should have re-compiled.
     contract = tmp_project.Other
     assert not contract.contract_type.methods
@@ -289,8 +289,8 @@ def test_extract_manifest_excludes_cache(tmp_project):
     cachefile = tmp_project.contracts_folder / ".cache" / "CacheFile.json"
     cachefile2 = tmp_project.contracts_folder / ".cache" / "subdir" / "Cache2.json"
     cachefile2.parent.mkdir(parents=True)
-    cachefile.write_text("Doesn't matter")
-    cachefile2.write_text("Doesn't matter")
+    cachefile.write_text("Doesn't matter", encoding="utf8")
+    cachefile2.write_text("Doesn't matter", encoding="utf8")
     manifest = tmp_project.extract_manifest()
     assert isinstance(manifest, PackageManifest)
     assert ".cache/CacheFile.json" not in (manifest.sources or {})
@@ -355,7 +355,7 @@ def test_load_contracts_detect_change(tmp_project, ape_caplog):
         new_content = content.replace("foo", "bar")
         assert "bar" in new_content, "Test setup failed. Unexpected file content."
         path.unlink()
-        path.write_text(new_content)
+        path.write_text(new_content, encoding="utf8")
 
         # Prove re-compiles.
         contracts = tmp_project.load_contracts()
@@ -375,7 +375,7 @@ def test_load_contracts_after_deleting_same_named_contract(tmp_project, compiler
     collision error from deleted files.
     """
     init_contract = tmp_project.contracts_folder / "foo.__mock__"
-    init_contract.write_text("LALA")
+    init_contract.write_text("LALA", encoding="utf8")
     compilers.registered_compilers[".__mock__"] = mock_compiler
     result = tmp_project.load_contracts()
     assert "foo" in result
@@ -390,7 +390,7 @@ def test_load_contracts_after_deleting_same_named_contract(tmp_project, compiler
 
     # Create a new contract with the same name.
     new_contract = tmp_project.contracts_folder / "bar.__mock__"
-    new_contract.write_text("BAZ")
+    new_contract.write_text("BAZ", encoding="utf8")
     mock_compiler.overrides = {"contractName": "foo"}
     result = tmp_project.load_contracts()
     assert "foo" in result
@@ -525,10 +525,10 @@ def test_project_api_foundry_and_ape_config_found(foundry_toml):
     """
     with ape.Project.create_temporary_project() as temp_project:
         foundry_cfg_file = temp_project.path / "foundry.toml"
-        foundry_cfg_file.write_text(foundry_toml)
+        foundry_cfg_file.write_text(foundry_toml, encoding="utf8")
 
         ape_cfg_file = temp_project.path / "ape-config.yaml"
-        ape_cfg_file.write_text("name: testfootestfootestfoo")
+        ape_cfg_file.write_text("name: testfootestfootestfoo", encoding="utf8")
 
         actual = temp_project.project_api
         assert isinstance(actual, ApeProject)
@@ -658,9 +658,9 @@ def gitmodules(self):
     def test_extract_config(self, foundry_toml, gitmodules, mock_github):
         with ape.Project.create_temporary_project() as temp_project:
             cfg_file = temp_project.path / "foundry.toml"
-            cfg_file.write_text(foundry_toml)
+            cfg_file.write_text(foundry_toml, encoding="utf8")
             gitmodules_file = temp_project.path / ".gitmodules"
-            gitmodules_file.write_text(gitmodules)
+            gitmodules_file.write_text(gitmodules, encoding="utf8")
 
             api = temp_project.project_api
             mock_github.get_repo.return_value = {"default_branch": "main"}
@@ -736,7 +736,7 @@ def clean():
             # Duplicate contract so that there are multiple with the same name.
             for nested_src in (nested_source_a, nested_source_b):
                 nested_src.touch()
-                nested_src.write_text(source_path.read_text())
+                nested_src.write_text(source_path.read_text(), encoding="utf8")
 
             # Top-level match.
             for base in (source_path, str(source_path), "Contract", "Contract.json"):
@@ -793,7 +793,7 @@ def test_paths_exclude(self, tmp_project):
             cache = tmp_project.contracts_folder / ".cache"
             cache.mkdir(exist_ok=True)
             random_file = cache / "dontmindme.json"
-            random_file.write_text("what, this isn't json?!")
+            random_file.write_text("what, this isn't json?!", encoding="utf8")
 
             path_ids = {
                 f"{tmp_project.contracts_folder.name}/{src.name}"
diff --git a/tests/integration/cli/test_accounts.py b/tests/integration/cli/test_accounts.py
index 1c6da566d0..8a565cf1fb 100644
--- a/tests/integration/cli/test_accounts.py
+++ b/tests/integration/cli/test_accounts.py
@@ -38,7 +38,7 @@ def temp_keyfile_path(config):
 
 @pytest.fixture
 def temp_keyfile(temp_keyfile_path, keyparams):
-    temp_keyfile_path.write_text(json.dumps(keyparams))
+    temp_keyfile_path.write_text(json.dumps(keyparams), encoding="utf8")
 
     yield temp_keyfile_path
 
diff --git a/tests/integration/cli/test_compile.py b/tests/integration/cli/test_compile.py
index c7822959a5..55897c8572 100644
--- a/tests/integration/cli/test_compile.py
+++ b/tests/integration/cli/test_compile.py
@@ -126,7 +126,7 @@ def test_compile_when_sources_change(ape_cli, runner, integ_project, clean_cache
     modified_source_text = source_path.read_text().replace("bar", "foo")
     source_path.unlink()
     source_path.touch()
-    source_path.write_text(modified_source_text)
+    source_path.write_text(modified_source_text, encoding="utf8")
     result = runner.invoke(
         ape_cli, ("compile", "--project", f"{integ_project.path}"), catch_exceptions=False
     )
@@ -160,7 +160,7 @@ def clean():
     temp_dir.mkdir()
     try:
         source_copy.touch()
-        source_copy.write_text(source_path.read_text())
+        source_copy.write_text(source_path.read_text(), encoding="utf8")
         result = runner.invoke(
             ape_cli, ("compile", "--project", f"{integ_project.path}"), catch_exceptions=False
         )
@@ -190,7 +190,7 @@ def test_compile_when_source_contains_return_characters(
     modified_source_text = f"{source_path.read_text()}\r"
     source_path.unlink()
     source_path.touch()
-    source_path.write_text(modified_source_text)
+    source_path.write_text(modified_source_text, encoding="utf8")
     arguments = ("compile", "--project", f"{integ_project.path}")
     result = runner.invoke(ape_cli, arguments, catch_exceptions=False)
     assert result.exit_code == 0, result.output
diff --git a/tests/integration/cli/test_console.py b/tests/integration/cli/test_console.py
index 26371c6e92..95df40ce5f 100644
--- a/tests/integration/cli/test_console.py
+++ b/tests/integration/cli/test_console.py
@@ -62,7 +62,7 @@ def no_console_error(result):
 
 def write_ape_console_extras(base_path, contents):
     extras_file = base_path.joinpath("ape_console_extras.py")
-    extras_file.write_text(contents)
+    extras_file.write_text(contents, encoding="utf8")
     return extras_file
 
 
diff --git a/tests/integration/cli/test_run.py b/tests/integration/cli/test_run.py
index 6f9db5836a..19b58609bc 100644
--- a/tests/integration/cli/test_run.py
+++ b/tests/integration/cli/test_run.py
@@ -206,7 +206,7 @@ def test_run_recompiles_if_needed(runner, ape_cli, scripts_runner, integ_project
     method_name = integ_project.VyperContract.contract_type.view_methods[0].name
     new_method_name = f"f__{method_name}__"
     new_contract_text = contract.read_text().replace(method_name, new_method_name)
-    contract.write_text(new_contract_text)
+    contract.write_text(new_contract_text, encoding="utf8")
 
     # Run the script. It better recompile first!
     result = scripts_runner.invoke("output_contract_view_methods")