diff --git a/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-groupby-thunk.exp b/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-groupby-thunk.exp
new file mode 100644
index 000000000..94649819c
--- /dev/null
+++ b/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-groupby-thunk.exp
@@ -0,0 +1 @@
+{ fred = [ { x = "fred"; y = "fred"; } ]; }
diff --git a/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-groupby-thunk.nix b/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-groupby-thunk.nix
new file mode 100644
index 000000000..d62ae628d
--- /dev/null
+++ b/tvix/eval/src/tests/tvix_tests/eval-okay-builtins-groupby-thunk.nix
@@ -0,0 +1,6 @@
+
+builtins.groupBy
+  (v: v.x)
+  [ (rec { y = x; x = "fred"; }) ]
+
+
diff --git a/tvix/verify-lang-tests/default.nix b/tvix/verify-lang-tests/default.nix
index ca7ea4b34..b526085bb 100644
--- a/tvix/verify-lang-tests/default.nix
+++ b/tvix/verify-lang-tests/default.nix
@@ -56,6 +56,8 @@ let
     "eval-okay-compare-lists.nix" = [ nix ];
     # getAttrPos gains support for functionArgs-returned sets after 2.3
     "eval-okay-getattrpos-functionargs.nix" = [ nix ];
+    # groupBy appeared (long) after 2.3
+    "eval-okay-builtins-groupby-thunk.nix" = [ nix ];
   };
 
   runCppNixLangTests = cpp-nix: