diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a60dad5d..0fd01285 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -156,7 +156,8 @@ jobs:
                 curl -L -O https://gitlab.tiker.net/inducer/ci-support/raw/main/ci-support.sh
                 . ci-support.sh
 
-                export EXTRA_INSTALL="sphinxcontrib-tikz"
+                # https://github.com/sphinx-contrib/tikz/issues/21
+                export EXTRA_INSTALL="sphinxcontrib-tikz!=0.4.18"
                 build_py_project_in_conda_env
 
                 # Work around
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 1fd428d0..618f9157 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -91,7 +91,8 @@ Python 3 Conda:
 
 Documentation:
   script:
-  - EXTRA_INSTALL="pybind11 cython numpy sphinxcontrib-tikz"
+  # https://github.com/sphinx-contrib/tikz/issues/21
+  - EXTRA_INSTALL="pybind11 cython numpy sphinxcontrib-tikz!=0.4.18"
   - curl -L -O https://gitlab.tiker.net/inducer/ci-support/raw/main/build-docs.sh
   - . ./build-docs.sh
   tags: