diff --git a/tests/benchmarks/corelib/tools/qhash/tst_bench_qhash.cpp b/tests/benchmarks/corelib/tools/qhash/tst_bench_qhash.cpp
index 9d9703dc0cd..b1fd446cb81 100644
--- a/tests/benchmarks/corelib/tools/qhash/tst_bench_qhash.cpp
+++ b/tests/benchmarks/corelib/tools/qhash/tst_bench_qhash.cpp
@@ -55,6 +55,8 @@ private:
 
 void tst_QHash::initTestCase()
 {
+    QHashSeed::setDeterministicGlobalSeed();
+
     // small list of strings (that happen to look like file paths produced long
     // ago by cd ../.. && find . -print, but that's irrelevant).
     QFile smallPathsData(QFINDTESTDATA("paths_small_data.txt"));
diff --git a/tests/benchmarks/corelib/tools/qset/tst_bench_qset.cpp b/tests/benchmarks/corelib/tools/qset/tst_bench_qset.cpp
index 9ac1a0449fa..e69f669007d 100644
--- a/tests/benchmarks/corelib/tools/qset/tst_bench_qset.cpp
+++ b/tests/benchmarks/corelib/tools/qset/tst_bench_qset.cpp
@@ -9,12 +9,18 @@ class tst_QSet : public QObject
     Q_OBJECT
 
 private slots:
+    void initTestCase();
     void intersect_int_data();
     void intersect_int();
     void intersect_complexType_data();
     void intersect_complexType();
 };
 
+void tst_QSet::initTestCase()
+{
+    QHashSeed::setDeterministicGlobalSeed();
+}
+
 void tst_QSet::intersect_int_data()
 {
     QTest::addColumn<int>("lhsSize");