diff --git a/.github/workflows/Fortran.yml b/.github/workflows/Fortran.yml
index 368085af7..4ae9fcbcb 100644
--- a/.github/workflows/Fortran.yml
+++ b/.github/workflows/Fortran.yml
@@ -130,7 +130,7 @@ jobs:
       - name: PETSc - Installation
         run: |
           cd petsc-${PETSC_VERSION}
-          ./configure --with-fc=gfortran-${GCC_V} --with-cc=gcc-${GCC_V} --with-cxx=g++-${GCC_V} \
+          COPTFLAGS='-O0' FOPTFLAGS='-O0' CXXOPTFLAGS='-O0' ./configure --with-fc=gfortran-${GCC_V} --with-cc=gcc-${GCC_V} --with-cxx=g++-${GCC_V} \
           --download-openmpi --download-fftw --download-hdf5 --download-zlib --download-make \
           --download-hdf5-fortran-bindings=1 --with-mpi-f90module-visibility=1
           make all