diff --git a/authorize/evaluator/headers_evaluator_evaluation.go b/authorize/evaluator/headers_evaluator_evaluation.go
index 8f099f88f..dfb531af7 100644
--- a/authorize/evaluator/headers_evaluator_evaluation.go
+++ b/authorize/evaluator/headers_evaluator_evaluation.go
@@ -272,8 +272,7 @@ func (e *headersEvaluatorEvaluation) getJWTPayloadEmail(ctx context.Context) str
 }
 
 func (e *headersEvaluatorEvaluation) getJWTPayloadGroups(ctx context.Context) []string {
-	groups := e.getFilteredGroups(ctx)
-
+	groups := e.getGroups(ctx)
 	if groups == nil {
 		// If there are no groups, marshal this claim as an empty list rather than a JSON null,
 		// for better compatibility with third-party libraries.
@@ -283,9 +282,22 @@ func (e *headersEvaluatorEvaluation) getJWTPayloadGroups(ctx context.Context) []
 	return groups
 }
 
-func (e *headersEvaluatorEvaluation) getFilteredGroups(ctx context.Context) []string {
-	groups := e.getAllGroups(ctx)
+func (e *headersEvaluatorEvaluation) getGroups(ctx context.Context) []string {
+	groupIDs := e.getGroupIDs(ctx)
+	if len(groupIDs) > 0 {
+		groupIDs = e.filterGroups(groupIDs)
+		groups := make([]string, 0, len(groupIDs)*2)
+		groups = append(groups, groupIDs...)
+		groups = append(groups, e.getDataBrokerGroupNames(ctx, groupIDs)...)
+		return groups
+	}
 
+	s, _ := e.getSessionOrServiceAccount(ctx)
+	groups, _ := getClaimStringSlice(s, "groups")
+	return groups
+}
+
+func (e *headersEvaluatorEvaluation) filterGroups(groups []string) []string {
 	// Apply the global groups filter or the per-route groups filter, if either is enabled.
 	filters := make([]config.JWTGroupsFilter, 0, 2)
 	if f := e.evaluator.store.GetJWTGroupsFilter(); f.Enabled() {
@@ -308,21 +320,6 @@ func (e *headersEvaluatorEvaluation) getFilteredGroups(ctx context.Context) []st
 	})
 }
 
-// getAllGroups returns the full group names/IDs list (without any filtering).
-func (e *headersEvaluatorEvaluation) getAllGroups(ctx context.Context) []string {
-	groupIDs := e.getGroupIDs(ctx)
-	if len(groupIDs) > 0 {
-		groups := make([]string, 0, len(groupIDs)*2)
-		groups = append(groups, groupIDs...)
-		groups = append(groups, e.getDataBrokerGroupNames(ctx, groupIDs)...)
-		return groups
-	}
-
-	s, _ := e.getSessionOrServiceAccount(ctx)
-	groups, _ := getClaimStringSlice(s, "groups")
-	return groups
-}
-
 func (e *headersEvaluatorEvaluation) getJWTPayloadSID() string {
 	return e.request.Session.ID
 }
diff --git a/authorize/evaluator/headers_evaluator_test.go b/authorize/evaluator/headers_evaluator_test.go
index 979111d1b..5108b34d3 100644
--- a/authorize/evaluator/headers_evaluator_test.go
+++ b/authorize/evaluator/headers_evaluator_test.go
@@ -551,6 +551,12 @@ func TestHeadersEvaluator_JWTGroupsFilter(t *testing.T) {
 			newDirectoryUserRecord(directory.User{ID: id, GroupIDs: groups}),
 		)
 	}
+	// Also add a user session with an upstream "groups" claim from the IdP.
+	records = append(records,
+		&session.Session{Id: "SESSION-11", UserId: "USER-11", Claims: map[string]*structpb.ListValue{
+			"groups": newList("foo", "bar", "baz"),
+		}},
+	)
 
 	cases := []struct {
 		name         string
@@ -559,18 +565,21 @@ func TestHeadersEvaluator_JWTGroupsFilter(t *testing.T) {
 		sessionID    string
 		expected     []any
 	}{
-		{"global filter 1", []string{"42", "1", "GROUP-12"}, nil, "SESSION-1", []any{"1", "42", "GROUP-12"}},
-		{"global filter 2", []string{"42", "1", "GROUP-12"}, nil, "SESSION-2", []any{"42", "GROUP-12"}},
-		{"route filter 1", nil, []string{"42", "1", "GROUP-12"}, "SESSION-1", []any{"1", "42", "GROUP-12"}},
-		{"route filter 2", nil, []string{"42", "1", "GROUP-12"}, "SESSION-2", []any{"42", "GROUP-12"}},
-		{"both filters 1", []string{"1"}, []string{"42", "GROUP-12"}, "SESSION-1", []any{"1", "42", "GROUP-12"}},
-		{"both filters 2", []string{"1"}, []string{"42", "GROUP-12"}, "SESSION-2", []any{"42", "GROUP-12"}},
-		{"overlapping", []string{"1"}, []string{"1"}, "SESSION-1", []any{"1"}},
-		{"empty route filter", []string{"1", "2", "3"}, []string{}, "SESSION-1", []any{"1", "2", "3"}},
+		{"global filter 1", []string{"42", "1"}, nil, "SESSION-1", []any{"1", "42", "GROUP-1", "GROUP-42"}},
+		{"global filter 2", []string{"42", "1"}, nil, "SESSION-2", []any{"42", "GROUP-42"}},
+		{"route filter 1", nil, []string{"42", "1"}, "SESSION-1", []any{"1", "42", "GROUP-1", "GROUP-42"}},
+		{"route filter 2", nil, []string{"42", "1"}, "SESSION-2", []any{"42", "GROUP-42"}},
+		{"both filters 1", []string{"1"}, []string{"42"}, "SESSION-1", []any{"1", "42", "GROUP-1", "GROUP-42"}},
+		{"both filters 2", []string{"1"}, []string{"42"}, "SESSION-2", []any{"42", "GROUP-42"}},
+		{"cannot filter by name", []string{"GROUP-1"}, nil, "SESSION-1", []any{}},
+		{"overlapping", []string{"1"}, []string{"1"}, "SESSION-1", []any{"1", "GROUP-1"}},
+		{"empty route filter", []string{"1", "2", "3"}, []string{}, "SESSION-1", []any{"1", "2", "3", "GROUP-1", "GROUP-2", "GROUP-3"}},
 		{
 			"no filtering", nil, nil, "SESSION-10",
 			[]any{"10", "20", "30", "40", "50", "GROUP-10", "GROUP-20", "GROUP-30", "GROUP-40", "GROUP-50"},
 		},
+		// filtering has no effect on groups from an IdP "groups" claim
+		{"groups claim", []string{"foo", "quux"}, nil, "SESSION-11", []any{"foo", "bar", "baz"}},
 	}
 
 	ctx := storage.WithQuerier(context.Background(), storage.NewStaticQuerier(records...))
@@ -647,3 +656,8 @@ func newDirectoryUserRecord(directoryUser directory.User) *databroker.Record {
 	s, _ := structpb.NewStruct(m)
 	return storage.NewStaticRecord(directory.UserRecordType, s)
 }
+
+func newList(v ...any) *structpb.ListValue {
+	lv, _ := structpb.NewList(v)
+	return lv
+}