diff --git a/src/main/java/org/pitest/junit5/JUnit5TestPluginFactory.java b/src/main/java/org/pitest/junit5/JUnit5TestPluginFactory.java
index f7444c3..2cb3a19 100755
--- a/src/main/java/org/pitest/junit5/JUnit5TestPluginFactory.java
+++ b/src/main/java/org/pitest/junit5/JUnit5TestPluginFactory.java
@@ -31,6 +31,7 @@ public Configuration createTestFrameworkConfiguration(TestGroupConfig config,
         ClassByteArraySource source, 
         Collection<String> excludedRunners,
         Collection<String> includedTestMethods) {
+        System.setProperty("junit.jupiter.execution.parallel.enabled", "false");
         return new JUnit5Configuration(config, includedTestMethods);
     }