diff --git a/.github/scripts/build.sh b/.github/scripts/build.sh
index 111257ae..b9c56926 100755
--- a/.github/scripts/build.sh
+++ b/.github/scripts/build.sh
@@ -17,8 +17,6 @@
 # Exit when any command fails.
 set -e
 
-PYTHON_VERSION=${PYTHON_VERSION:-3.7}
-
 pip install -U -r .github/scripts/requirements.txt
 python setup.py develop
 python -m pytest  # Run the tests without IPython.
diff --git a/examples/diff/diff.py b/examples/diff/diff.py
index f99e525e..ea64a0ef 100644
--- a/examples/diff/diff.py
+++ b/examples/diff/diff.py
@@ -14,10 +14,6 @@
 
 r"""A command line tool for diffing files.
 
-The Python 2.7 documentation demonstrates how to make a command line interface
-for the difflib library using optparse:
-https://docs.python.org/2/library/difflib.html#a-command-line-interface-to-difflib
-
 This file demonstrates how to create a command line interface providing the same
 functionality using Python Fire.
 
diff --git a/fire/console/platforms.py b/fire/console/platforms.py
index 13fd8204..b3d9d82a 100644
--- a/fire/console/platforms.py
+++ b/fire/console/platforms.py
@@ -378,19 +378,10 @@ def AsyncPopenArgs(self):
 
 
 class PythonVersion(object):
-  """Class to validate the Python version we are using.
-
-  The Cloud SDK officially supports Python 2.7.
-
-  However, many commands do work with Python 2.6, so we don't error out when
-  users are using this (we consider it sometimes "compatible" but not
-  "supported").
-  """
+  """Class to validate the Python version we are using."""
 
   # See class docstring for descriptions of what these mean
-  MIN_REQUIRED_PY2_VERSION = (2, 6)
-  MIN_SUPPORTED_PY2_VERSION = (2, 7)
-  MIN_SUPPORTED_PY3_VERSION = (3, 4)
+  MIN_SUPPORTED_PY3_VERSION = (3, 5)
   ENV_VAR_MESSAGE = """\
 
 If you have a compatible Python interpreter installed, you can use it by setting
@@ -406,29 +397,17 @@ def __init__(self, version=None):
     else:
       self.version = None
 
-  def SupportedVersionMessage(self, allow_py3):
-    if allow_py3:
-      return 'Please use Python version {0}.{1}.x or {2}.{3} and up.'.format(
-          PythonVersion.MIN_SUPPORTED_PY2_VERSION[0],
-          PythonVersion.MIN_SUPPORTED_PY2_VERSION[1],
-          PythonVersion.MIN_SUPPORTED_PY3_VERSION[0],
-          PythonVersion.MIN_SUPPORTED_PY3_VERSION[1])
-    else:
-      return 'Please use Python version {0}.{1}.x.'.format(
-          PythonVersion.MIN_SUPPORTED_PY2_VERSION[0],
-          PythonVersion.MIN_SUPPORTED_PY2_VERSION[1])
+  def SupportedVersionMessage(self):
+    return 'Please use Python version {0}.{1} and up.'.format(
+        PythonVersion.MIN_SUPPORTED_PY3_VERSION[0],
+        PythonVersion.MIN_SUPPORTED_PY3_VERSION[1])
 
-  def IsCompatible(self, allow_py3=False, raise_exception=False):
+  def IsCompatible(self, raise_exception=False):
     """Ensure that the Python version we are using is compatible.
 
     This will print an error message if not compatible.
 
-    Compatible versions are 2.6 and 2.7 and > 3.4 if allow_py3 is True.
-    We don't guarantee support for 2.6 so we want to warn about it.
-
     Args:
-      allow_py3: bool, True if we should allow a Python 3 interpreter to run
-        gcloud. If False, this returns an error for Python 3.
       raise_exception: bool, True to raise an exception rather than printing
         the error and exiting.
 
@@ -443,26 +422,14 @@ def IsCompatible(self, allow_py3=False, raise_exception=False):
       # We don't know the version, not a good sign.
       error = ('ERROR: Your current version of Python is not compatible with '
                'the Google Cloud SDK. {0}\n'
-               .format(self.SupportedVersionMessage(allow_py3)))
+               .format(self.SupportedVersionMessage()))
     else:
-      if self.version[0] < 3:
-        # Python 2 Mode
-        if self.version < PythonVersion.MIN_REQUIRED_PY2_VERSION:
-          error = ('ERROR: Python {0}.{1} is not compatible with the Google '
-                   'Cloud SDK. {2}\n'
-                   .format(self.version[0], self.version[1],
-                           self.SupportedVersionMessage(allow_py3)))
-      else:
-        # Python 3 Mode
-        if not allow_py3:
-          error = ('ERROR: Python 3 and later is not compatible with the '
-                   'Google Cloud SDK. {0}\n'
-                   .format(self.SupportedVersionMessage(allow_py3)))
-        elif self.version < PythonVersion.MIN_SUPPORTED_PY3_VERSION:
-          error = ('ERROR: Python {0}.{1} is not compatible with the Google '
-                   'Cloud SDK. {2}\n'
-                   .format(self.version[0], self.version[1],
-                           self.SupportedVersionMessage(allow_py3)))
+      # Python 3 Mode
+      if self.version < PythonVersion.MIN_SUPPORTED_PY3_VERSION:
+        error = ('ERROR: Python {0}.{1} is not compatible with the Google '
+                 'Cloud SDK. {2}\n'
+                 .format(self.version[0], self.version[1],
+                         self.SupportedVersionMessage()))
 
     if error:
       if raise_exception:
@@ -471,13 +438,4 @@ def IsCompatible(self, allow_py3=False, raise_exception=False):
       sys.stderr.write(PythonVersion.ENV_VAR_MESSAGE)
       return False
 
-    # Warn that 2.6 might not work.
-    if (self.version >= self.MIN_REQUIRED_PY2_VERSION and
-        self.version < self.MIN_SUPPORTED_PY2_VERSION):
-      sys.stderr.write("""\
-WARNING:  Python 2.6.x is no longer officially supported by the Google Cloud SDK
-and may not function correctly.  {0}
-{1}""".format(self.SupportedVersionMessage(allow_py3),
-              PythonVersion.ENV_VAR_MESSAGE))
-
     return True
diff --git a/fire/inspectutils.py b/fire/inspectutils.py
index a3ae7c27..eac417c0 100644
--- a/fire/inspectutils.py
+++ b/fire/inspectutils.py
@@ -166,12 +166,8 @@ def GetFullArgSpec(fn):
   fn, skip_arg = _GetArgSpecInfo(fn)
 
   try:
-    if sys.version_info[0:2] >= (3, 5):
-      (args, varargs, varkw, defaults,
+    (args, varargs, varkw, defaults,
        kwonlyargs, kwonlydefaults, annotations) = Py3GetFullArgSpec(fn)
-    else:  # Specifically Python 3.4.
-      (args, varargs, varkw, defaults,
-       kwonlyargs, kwonlydefaults, annotations) = inspect.getfullargspec(fn)  # pylint: disable=deprecated-method,no-member
 
   except TypeError:
     # If we can't get the argspec, how do we know if the fn should take args?
@@ -200,9 +196,7 @@ def GetFullArgSpec(fn):
     # Case 3: Other known slot wrappers do not accept args.
     return FullArgSpec()
 
-  # In Python 3.5+ Py3GetFullArgSpec uses skip_bound_arg=True already.
-  skip_arg_required = sys.version_info[0:2] == (3, 4)
-  if skip_arg_required and skip_arg and args:
+  if skip_arg and args:
     args.pop(0)  # Remove 'self' or 'cls' from the list of arguments.
   return FullArgSpec(args, varargs, varkw, defaults,
                      kwonlyargs, kwonlydefaults, annotations)
diff --git a/setup.py b/setup.py
index 82073be4..51dda0c6 100644
--- a/setup.py
+++ b/setup.py
@@ -46,6 +46,7 @@
     description=SHORT_DESCRIPTION,
     long_description=LONG_DESCRIPTION,
     url=URL,
+    python_requires='>=3.5',
 
     author='David Bieber',
     author_email='dbieber@google.com',
@@ -61,6 +62,9 @@
 
         'Programming Language :: Python',
         'Programming Language :: Python :: 3',
+        'Programming Language :: Python :: 3 :: Only',
+        'Programming Language :: Python :: 3.5',
+        'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: 3.8',
         'Programming Language :: Python :: 3.9',