diff --git a/tests/src/test/java/org/mozilla/javascript/tests/SecurityControllerTest.java b/tests/src/test/java/org/mozilla/javascript/tests/SecurityControllerTest.java
index 1ffbcc6f85..defc10c305 100644
--- a/tests/src/test/java/org/mozilla/javascript/tests/SecurityControllerTest.java
+++ b/tests/src/test/java/org/mozilla/javascript/tests/SecurityControllerTest.java
@@ -13,6 +13,9 @@
 import java.security.ProtectionDomain;
 import java.security.URIParameter;
 import java.util.Enumeration;
+
+import org.hamcrest.CoreMatchers;
+import org.junit.Assume;
 import org.junit.BeforeClass;
 import org.junit.Test;
 import org.mozilla.javascript.ClassShutter;
@@ -36,6 +39,7 @@ static void setupSecurityManager() {}
     /** Setup the security */
     @BeforeClass
     public static void setup() throws Exception {
+        Assume.assumeThat("Skipping test for Java 21", Utils.isJavaVersionAtLeast(21), CoreMatchers.is(false));
         URL url = SecurityControllerTest.class.getResource("grant-all-java.policy");
         if (url != null) {
             System.setProperty("java.security.policy", url.toString());
@@ -69,6 +73,9 @@ private static ProtectionDomain createProtectionDomain(Policy policy, String csS
 
     @Test
     public void barAccess() {
+        // Security managers are out in Java 21, so skip.
+        Assume.assumeThat("Skipping test for Java 21", Utils.isJavaVersionAtLeast(21), CoreMatchers.is(false));
+
         // f.create produces "SomeClass extends ArrayList<String> implements
         // SomeInterface"
         // we may access array methods, like 'size' defined by ArrayList,
diff --git a/tests/src/test/java/org/mozilla/javascript/tests/Utils.java b/tests/src/test/java/org/mozilla/javascript/tests/Utils.java
index 76dab93284..ac7d7d0d94 100644
--- a/tests/src/test/java/org/mozilla/javascript/tests/Utils.java
+++ b/tests/src/test/java/org/mozilla/javascript/tests/Utils.java
@@ -77,4 +77,10 @@ public static int[] getTestOptLevels() {
         }
         return DEFAULT_OPT_LEVELS;
     }
+
+    public static boolean isJavaVersionAtLeast(int desiredVersion) {
+        String[] v = System.getProperty("java.version").split("\\.");
+        int version = Integer.parseInt(v[0]);
+        return version >= desiredVersion;
+    }
 }