diff --git a/non_module_dev_deps.bzl b/non_module_dev_deps.bzl
index 44f5cd1ff..1b0bd861b 100644
--- a/non_module_dev_deps.bzl
+++ b/non_module_dev_deps.bzl
@@ -119,7 +119,7 @@ def repositories(*, bzlmod):
 
     nixpkgs_package(
         name = "sphinx",
-        attribute_path = "python39Packages.sphinx",
+        attribute_path = "python3Packages.sphinx",
         repository = "@nixpkgs_default",
     )
 
diff --git a/rules_haskell_tests/shell.nix b/rules_haskell_tests/shell.nix
index d3169348a..b9276dcfb 100644
--- a/rules_haskell_tests/shell.nix
+++ b/rules_haskell_tests/shell.nix
@@ -31,7 +31,7 @@ mkShell {
     # check the start script for problems
     shellcheck
     file
-  ] ++ lib.optionals docTools [ graphviz python39Packages.sphinx zip unzip ];
+  ] ++ lib.optionals docTools [ graphviz python3Packages.sphinx zip unzip ];
 
   packages = [ bazel_6 ];
 
diff --git a/shell.nix b/shell.nix
index 38a21a923..1a6893ad3 100644
--- a/shell.nix
+++ b/shell.nix
@@ -39,7 +39,7 @@ mkShell {
     shellcheck
     file
   ]
-  ++ lib.optionals docTools [ graphviz python39Packages.sphinx zip unzip ]
+  ++ lib.optionals docTools [ graphviz python3Packages.sphinx zip unzip ]
   ++ lib.optional stdenv.isDarwin macOS-security;
 
   packages = [ bazel_6 ];