diff --git a/.github/workflows/build_and_test.yml b/.github/workflows/build_and_test.yml
index 5a1e456c5..76a9b21ae 100644
--- a/.github/workflows/build_and_test.yml
+++ b/.github/workflows/build_and_test.yml
@@ -1,4 +1,4 @@
-name: Build Package and Test Source Code [Python 3.9, 3.10, 3.11, 3.12]
+name: Build Package and Test Source Code [Python 3.10, 3.11, 3.12]
 
 on: [push, pull_request]
 
@@ -8,7 +8,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, windows-latest]
-        python-version: [3.9, '3.10', '3.11', '3.12']
+        python-version: ['3.10', '3.11', '3.12']
 
     steps:
       - name: Checkout
diff --git a/.github/workflows/check_jupyterbook.yml b/.github/workflows/check_jupyterbook.yml
index 4a491fe5e..f0eb02d70 100644
--- a/.github/workflows/check_jupyterbook.yml
+++ b/.github/workflows/check_jupyterbook.yml
@@ -15,7 +15,7 @@ jobs:
         with:
           activate-environment: taxcalc-dev
           environment-file: environment.yml
-          python-version: 3.11
+          python-version: 3.12
           auto-activate-base: false
 
       - name: Build # Build Jupyter Book
diff --git a/.github/workflows/deploy_jupyterbook.yml b/.github/workflows/deploy_jupyterbook.yml
index 87c36b992..8242d7cbc 100644
--- a/.github/workflows/deploy_jupyterbook.yml
+++ b/.github/workflows/deploy_jupyterbook.yml
@@ -18,7 +18,7 @@ jobs:
         with:
           activate-environment: taxcalc-dev
           environment-file: environment.yml
-          python-version: 3.11
+          python-version: 3.12
           auto-activate-base: false
 
       - name: Build # Build Jupyter Book
diff --git a/.github/workflows/deploy_parameters_docs.yml b/.github/workflows/deploy_parameters_docs.yml
index f3342557f..e2ed91c5d 100644
--- a/.github/workflows/deploy_parameters_docs.yml
+++ b/.github/workflows/deploy_parameters_docs.yml
@@ -18,7 +18,7 @@ jobs:
         with:
           activate-environment: taxcalc-dev
           environment-file: environment.yml
-          python-version: 3.11
+          python-version: 3.12
           auto-activate-base: false
 
       - name: Build # Build Jupyter Book