diff --git a/.azure-pipelines/linux_build.yml b/.azure-pipelines/linux_build.yml
index 1e50586379..f402b8c3d1 100644
--- a/.azure-pipelines/linux_build.yml
+++ b/.azure-pipelines/linux_build.yml
@@ -9,7 +9,7 @@ steps:
         boost-cpp=$(boost_version) boost=$(boost_version) \
         py-boost=$(boost_version) \
         numpy matplotlib pillow eigen pandas \
-        sphinx recommonmark jupyter
+        sphinx=3.1.2 recommonmark jupyter
     conda activate rdkit_build
     conda install -c rdkit nox cairo=1.14.6
   displayName: Setup build environment
diff --git a/.azure-pipelines/mac_build.yml b/.azure-pipelines/mac_build.yml
index e25fb1800d..737ae05194 100644
--- a/.azure-pipelines/mac_build.yml
+++ b/.azure-pipelines/mac_build.yml
@@ -21,7 +21,7 @@ steps:
         boost-cpp=$(boost_version) boost=$(boost_version) \
         py-boost=$(boost_version) libboost=$(boost_version) \
         numpy matplotlib cairo pillow eigen pandas  \
-        sphinx recommonmark jupyter
+        sphinx=3.1.2 recommonmark jupyter
   displayName: Setup build environment
 - bash: |
     source ${CONDA}/etc/profile.d/conda.sh
diff --git a/.azure-pipelines/vs_build.yml b/.azure-pipelines/vs_build.yml
index 6e078ca01b..2382c508e7 100644
--- a/.azure-pipelines/vs_build.yml
+++ b/.azure-pipelines/vs_build.yml
@@ -8,7 +8,7 @@ steps:
         boost-cpp=$(boost_version) boost=$(boost_version) ^
         py-boost=$(boost_version) libboost=$(boost_version) ^
         numpy matplotlib cairo pillow eigen pandas  ^
-        sphinx recommonmark jupyter
+        sphinx=3.1.2 recommonmark jupyter
   displayName: Install dependencies
 - script: |
     set Boost_ROOT=