diff --git a/.github/workflows/cmake.yml b/.github/workflows/cmake.yml
index 69bd538..e258b64 100644
--- a/.github/workflows/cmake.yml
+++ b/.github/workflows/cmake.yml
@@ -11,50 +11,59 @@ jobs:
           - name: Ubuntu GCC
             os: ubuntu-latest
             compiler: gcc
+            cflags: -Werror -Wall -Wextra
 
           # Test out of source builds
           - name: Ubuntu GCC OSB
             os: ubuntu-latest
             compiler: gcc
+            cflags: -Werror -Wall -Wextra
             build-dir: ../build
             src-dir: ../zlib
 
           - name: Ubuntu GCC -O3
             os: ubuntu-latest
             compiler: gcc
-            cflags: -O3
+            cflags: -O3 -Werror -Wall -Wextra
 
           - name: Ubuntu Clang
             os: ubuntu-latest
             compiler: clang
+            cflags: -Werror -Wall -Wextra
 
           - name: Ubuntu Clang Debug
             os: ubuntu-latest
             compiler: clang
+            cflags: -Werror -Wall -Wextra
             build-config: Debug
 
           - name: Windows MSVC Win32
             os: windows-latest
             compiler: cl
+            cflags: /WX /W3
             cmake-args: -A Win32
 
           - name: Windows MSVC Win64
             os: windows-latest
             compiler: cl
+            cflags: /WX /W3
             cmake-args: -A x64
 
           - name: Windows GCC
             os: windows-latest
             compiler: gcc
+            cflags: -Werror -Wall -Wextra
             cmake-args: -G Ninja
 
           - name: macOS Clang
             os: macos-latest
             compiler: clang
+            cflags: -Werror -Wall -Wextra
 
           - name: macOS GCC
             os: macos-latest
             compiler: gcc-11
+            cflags: -Werror -Wall -Wextra
 
     steps:
     - name: Checkout repository
diff --git a/.github/workflows/configure.yml b/.github/workflows/configure.yml
index 14a5a18..0d71689 100644
--- a/.github/workflows/configure.yml
+++ b/.github/workflows/configure.yml
@@ -110,7 +110,7 @@ jobs:
         ${{ matrix.src-dir || '.' }}/configure ${{ matrix.configure-args }}
       env:
         CC: ${{ matrix.compiler }}
-        CFLAGS: ${{ matrix.cflags }}
+        CFLAGS: ${{ matrix.cflags }} -Werror
         LDFLAGS: ${{ matrix.ldflags }}
         CHOST: ${{ matrix.chost }}