diff --git a/pkgs/by-name/pe/petsc/package.nix b/pkgs/by-name/pe/petsc/package.nix
index 03aeaeaeec86..ed989be6f710 100644
--- a/pkgs/by-name/pe/petsc/package.nix
+++ b/pkgs/by-name/pe/petsc/package.nix
@@ -10,7 +10,6 @@
   bison,
   mpi, # generic mpi dependency
   mpiCheckPhaseHook,
-  python3,
   python3Packages,
 
   # Build options
@@ -78,7 +77,6 @@ let
   petscPackages = lib.makeScope newScope (self: {
     inherit
       mpi
-      python3
       python3Packages
       # global override options
       mpiSupport
@@ -121,10 +119,10 @@ stdenv.mkDerivation (finalAttrs: {
   strictDeps = true;
 
   nativeBuildInputs = [
-    python3
     gfortran
     pkg-config
     bison
+    python3Packages.python
   ]
   ++ lib.optional mpiSupport mpi
   ++ lib.optionals pythonSupport [
@@ -154,7 +152,7 @@ stdenv.mkDerivation (finalAttrs: {
 
   patches = [
     (replaceVars ./fix-petsc4py-install-prefix.patch {
-      PYTHON_SITEPACKAGES = python3.sitePackages;
+      PYTHON_SITEPACKAGES = python3Packages.python.sitePackages;
     })
   ];
 
diff --git a/pkgs/by-name/sl/slepc/package.nix b/pkgs/by-name/sl/slepc/package.nix
index b44717b8b520..8e9e73833b67 100644
--- a/pkgs/by-name/sl/slepc/package.nix
+++ b/pkgs/by-name/sl/slepc/package.nix
@@ -2,7 +2,6 @@
   lib,
   stdenv,
   fetchFromGitLab,
-  python3,
   python3Packages,
   arpack-mpi,
   petsc,
@@ -29,7 +28,7 @@ stdenv.mkDerivation (finalAttrs: {
     # Fix slepc4py install prefix
     substituteInPlace config/packages/slepc4py.py \
       --replace-fail "slepc.prefixdir,'lib'" \
-      "slepc.prefixdir,'${python3.sitePackages}'"
+      "slepc.prefixdir,'${python3Packages.python.sitePackages}'"
 
     patchShebangs lib/slepc/bin
   '';
@@ -43,7 +42,7 @@ stdenv.mkDerivation (finalAttrs: {
   '';
 
   nativeBuildInputs = [
-    python3
+    python3Packages.python
   ]
   ++ lib.optionals pythonSupport [
     python3Packages.setuptools
diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index 82b48a2913d5..9fd74a1d5ebe 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -11561,7 +11561,6 @@ self: super: with self; {
 
   petsc4py = toPythonModule (
     pkgs.petsc.override {
-      python3 = python;
       python3Packages = self;
       pythonSupport = true;
     }
@@ -16798,7 +16797,6 @@ self: super: with self; {
   slepc4py = toPythonModule (
     pkgs.slepc.override {
       pythonSupport = true;
-      python3 = self.python;
       python3Packages = self;
       petsc = petsc4py;
     }