diff --git a/pkgs/development/libraries/tk/8.5.nix b/pkgs/development/libraries/tk/8.5.nix
index 3058af46ab57..c5d5c478c670 100644
--- a/pkgs/development/libraries/tk/8.5.nix
+++ b/pkgs/development/libraries/tk/8.5.nix
@@ -1,4 +1,11 @@
-{ callPackage, fetchurl, tcl, ... } @ args:
+{ lib
+, stdenv
+, callPackage
+, fetchurl
+, fetchpatch
+, tcl
+, ...
+} @ args:
 
 callPackage ./generic.nix (args // {
 
@@ -7,4 +14,15 @@ callPackage ./generic.nix (args // {
     sha256 = "0an3wqkjzlyyq6l9l3nawz76axsrsppbyylx0zk9lkv7llrala03";
   };
 
+  patches = lib.optionals stdenv.isDarwin [
+    # Define MODULE_SCOPE before including tkPort.h
+    # https://core.tcl-lang.org/tk/info/dba9f5ce3b
+    (fetchpatch {
+      name = "module_scope.patch";
+      url = "https://core.tcl-lang.org/tk/vpatch?from=ef6c6960c53ea30c&to=9b8aa74eebed509a";
+      extraPrefix = "";
+      sha256 = "0crhf4zrzdpc1jdgyv6l6mxqgmny12r3i39y1i0j8q3pbqkd04bv";
+    })
+  ];
+
 })
diff --git a/pkgs/development/libraries/tk/8.6.nix b/pkgs/development/libraries/tk/8.6.nix
index 33e3f8e41675..c4825d2ccf9d 100644
--- a/pkgs/development/libraries/tk/8.6.nix
+++ b/pkgs/development/libraries/tk/8.6.nix
@@ -1,4 +1,11 @@
-{ callPackage, fetchurl, tcl, lib, stdenv, ... } @ args:
+{ lib
+, stdenv
+, callPackage
+, fetchurl
+, fetchpatch
+, tcl
+, ...
+} @ args:
 
 callPackage ./generic.nix (args // {
 
@@ -7,6 +14,16 @@ callPackage ./generic.nix (args // {
     sha256 = "1gh9k7l76qg9l0sb78ijw9xz4xl1af47aqbdifb6mjpf3cbsnv00";
   };
 
-  patches = [ ./different-prefix-with-tcl.patch ] ++ lib.optionals stdenv.isDarwin [ ./Fix-bad-install_name-for-libtk8.6.dylib.patch ];
+  patches = [ ./different-prefix-with-tcl.patch ] ++ lib.optionals stdenv.isDarwin [
+    ./Fix-bad-install_name-for-libtk8.6.dylib.patch
+    # Define MODULE_SCOPE before including tkPort.h
+    # https://core.tcl-lang.org/tk/info/dba9f5ce3b
+    (fetchpatch {
+      name = "module_scope.patch";
+      url = "https://core.tcl-lang.org/tk/vpatch?from=ef6c6960c53ea30c&to=9b8aa74eebed509a";
+      extraPrefix = "";
+      sha256 = "0crhf4zrzdpc1jdgyv6l6mxqgmny12r3i39y1i0j8q3pbqkd04bv";
+    })
+  ];
 
 })