diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 2aed69db9d..3775bc2ce5 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -53,6 +53,12 @@ jobs:
           - name: Build mlibc
             run: 'xbstrap install ${{matrix.builds}}'
             working-directory: build/
+          - name: Check public headers conform to C89
+            working-directory: build/
+            run: |
+                tree
+                printf -- '-include\0%s\0' pkg-builds/${{matrix.builds}}/public-headers/usr/local/include/**.h | \
+                  xargs -0 gcc -x c -S /dev/null -o /dev/null -I pkg-builds/${{matrix.builds}}/public-headers/usr/local/include -nostdlib -std=c89 -Wpedantic -Werror
           - name: Test mlibc
             run: 'meson test -v -C pkg-builds/${{matrix.builds}}'
             working-directory: build/