diff --git a/jcl/src/java.management/share/classes/com/ibm/java/lang/management/internal/CompilationMXBeanImpl.java b/jcl/src/java.management/share/classes/com/ibm/java/lang/management/internal/CompilationMXBeanImpl.java
index 480e8fca6a0..bae3318d3d0 100644
--- a/jcl/src/java.management/share/classes/com/ibm/java/lang/management/internal/CompilationMXBeanImpl.java
+++ b/jcl/src/java.management/share/classes/com/ibm/java/lang/management/internal/CompilationMXBeanImpl.java
@@ -72,7 +72,12 @@ public static CompilationMXBeanImpl getInstance() {
 	 */
 	@Override
 	public String getName() {
-		return com.ibm.oti.vm.VM.getVMLangAccess().internalGetProperties().getProperty("java.compiler"); //$NON-NLS-1$
+		return com.ibm.oti.vm.VM.getVMLangAccess().internalGetProperties().
+/*[IF JAVA_SPEC_VERSION < 21]*/
+				getProperty("java.compiler"); //$NON-NLS-1$
+/*[ELSE] JAVA_SPEC_VERSION < 21 */
+				getProperty("openj9.compiler"); //$NON-NLS-1$
+/*[ENDIF] JAVA_SPEC_VERSION < 21*/
 	}
 
 	/**
diff --git a/runtime/include/vmi.h b/runtime/include/vmi.h
index 7c16c58e2fb..f5846ce7c1d 100644
--- a/runtime/include/vmi.h
+++ b/runtime/include/vmi.h
@@ -276,7 +276,7 @@ GetInitArgs(VMInterface* vmi);
 <BR>OpenJ9   - 1ca0ab98
 <BR>OMR      - 05d2b8a2
 <BR>JCL      - c2aa0348 based on jdk8u172-b11"</TD></TR>
- * <TR><TD>java.compiler</TD>			<TD>"j9jit29"</TD></TR>
+ * <TR><TD>java.compiler</TD>			<TD>"j9jit29" - not supported from jdk21</TD></TR>
  * <TR><TD>java.class.version</TD>		<TD>"52.0"</TD></TR>
  * <TR><TD>java.home</TD>			<TD>the absolute path of the parent directory of the directory containing the vm
 <BR>i.e. for a vm /clear/bin/vm.exe, java.home is /clear</TD></TR>
diff --git a/runtime/jcl/common/system.c b/runtime/jcl/common/system.c
index fde6411f43e..9a46a056012 100644
--- a/runtime/jcl/common/system.c
+++ b/runtime/jcl/common/system.c
@@ -36,6 +36,7 @@
 #include "jclprots.h"
 
 #include "ut_j9jcl.h"
+#include "j9jclnls.h"
 
 #if defined(J9ZOS390)
 #include "atoe.h"
@@ -551,6 +552,17 @@ systemPropertyIterator(char* key, char* value, void* userData)
 		return;
 	}
 
+#if JAVA_SPEC_VERSION >= 21
+	if (0 == strcmp("java.compiler", key)) {
+		PORT_ACCESS_FROM_ENV(env);
+		if ((0 == strcmp("jitc", value)) || (0 == strcmp(J9_JIT_DLL_NAME, value))) {
+			j9nls_printf(PORTLIB, J9NLS_WARNING, J9NLS_JCL_JAVA_COMPILER_WARNING_XJIT);
+		} else {
+			j9nls_printf(PORTLIB, J9NLS_WARNING, J9NLS_JCL_JAVA_COMPILER_WARNING_XINT);
+		}
+		return;
+	}
+#endif /* JAVA_SPEC_VERSION >= 21 */
 
 	/* check for overridden system properties, use linear scan for now */
 	for (i=0; i < defaultCount; i+=2) {
diff --git a/runtime/nls/j9cl/j9jcl.nls b/runtime/nls/j9cl/j9jcl.nls
index 0a0c30cfdaf..cb1067bc754 100644
--- a/runtime/nls/j9cl/j9jcl.nls
+++ b/runtime/nls/j9cl/j9jcl.nls
@@ -588,3 +588,21 @@ J9NLS_JCL_CRIU_FAILED_TO_ENABLE_ALL_RESTORE_OPTIONS.explanation=CRIUSupport::che
 J9NLS_JCL_CRIU_FAILED_TO_ENABLE_ALL_RESTORE_OPTIONS.system_action=The JVM will throw a JVMRestoreException.
 J9NLS_JCL_CRIU_FAILED_TO_ENABLE_ALL_RESTORE_OPTIONS.user_response=Check documentation to see which options are allowed on restore.
 # END NON-TRANSLATABLE
+
+# Note: "java.compiler" is a system property name and should not be translated.
+# Note: "-Xjit" is a command line parameter and should not be translated.
+J9NLS_JCL_JAVA_COMPILER_WARNING_XJIT=Setting the java.compiler system property is obsolete in version 21 and later, use -Xjit instead.
+# START NON-TRANSLATABLE
+J9NLS_JCL_JAVA_COMPILER_WARNING_XJIT.explanation=The java.compiler system property can no longer be used to enable or disable the JIT.
+J9NLS_JCL_JAVA_COMPILER_WARNING_XJIT.system_action=Setting the java.compiler system property is ignored.
+J9NLS_JCL_JAVA_COMPILER_WARNING_XJIT.user_response=Use the -Xjit option to enable the JIT.
+# END NON-TRANSLATABLE
+
+# Note: "java.compiler" is a system property name and should not be translated.
+# Note: "-Xint" is a command line parameter and should not be translated.
+J9NLS_JCL_JAVA_COMPILER_WARNING_XINT=Setting the java.compiler system property is obsolete in version 21 and later, use -Xint instead.
+# START NON-TRANSLATABLE
+J9NLS_JCL_JAVA_COMPILER_WARNING_XINT.explanation=The java.compiler system property can no longer be used to enable or disable the JIT.
+J9NLS_JCL_JAVA_COMPILER_WARNING_XINT.system_action=Setting the java.compiler system property is ignored.
+J9NLS_JCL_JAVA_COMPILER_WARNING_XINT.user_response=Use the -Xint option to disable the JIT.
+# END NON-TRANSLATABLE
diff --git a/runtime/util/vmargs.c b/runtime/util/vmargs.c
index ec2e2dbc89a..416916a4fc2 100644
--- a/runtime/util/vmargs.c
+++ b/runtime/util/vmargs.c
@@ -1388,7 +1388,9 @@ addEnvironmentVariables(J9PortLibrary *portLib, JavaVMInitArgs *launcherArgs, J9
 	IDATA status = 0;
 	if (
 			(0 != mapEnvVarToArgument(portLib, ENVVAR_IBM_MIXED_MODE_THRESHOLD, MAPOPT_XJIT_COUNT_EQUALS, vmArgumentsList, EXACT_MAP_WITH_OPTIONS, verboseFlags))
+#if JAVA_SPEC_VERSION < 21
 			|| (0 != mapEnvVarToArgument(portLib, ENVVAR_JAVA_COMPILER, SYSPROP_DJAVA_COMPILER_EQUALS, vmArgumentsList, EXACT_MAP_WITH_OPTIONS, verboseFlags))
+#endif /* JAVA_SPEC_VERSION < 21 */
 			|| (0 != mapEnvVarToArgument(portLib, ENVVAR_IBM_NOSIGHANDLER, VMOPT_XRS, vmArgumentsList, EXACT_MAP_NO_OPTIONS, verboseFlags))
 #if defined(J9ZOS390)
 			|| (0 != mapEnvVarToArgument(portLib, ENVVAR_JAVA_THREAD_MODEL, MAPOPT_XTHR_TW_EQUALS, vmArgumentsList, EXACT_MAP_WITH_OPTIONS, verboseFlags))
diff --git a/runtime/vm/jvminit.c b/runtime/vm/jvminit.c
index ce08e211ce3..10560341820 100644
--- a/runtime/vm/jvminit.c
+++ b/runtime/vm/jvminit.c
@@ -266,9 +266,9 @@ static void loadDLL (void* dllLoadInfo, void* userDataTemp);
 static void registerIgnoredOptions (J9PortLibrary *portLibrary, J9VMInitArgs* j9vm_args);
 static UDATA protectedInitializeJavaVM (J9PortLibrary* portLibrary, void * userData);
 static J9Pool *initializeDllLoadTable (J9PortLibrary *portLibrary, J9VMInitArgs* j9vm_args, UDATA verboseFlags, J9JavaVM *vm);
-#if (defined(J9VM_OPT_SIDECAR))
+#if defined(J9VM_OPT_SIDECAR) && (JAVA_SPEC_VERSION < 21)
 static IDATA checkDjavacompiler (J9PortLibrary *portLibrary, J9VMInitArgs* j9vm_args);
-#endif /* J9VM_OPT_SIDECAR */
+#endif /* defined(J9VM_OPT_SIDECAR) && (JAVA_SPEC_VERSION < 21) */
 static void* getOptionExtraInfo (J9PortLibrary *portLibrary, J9VMInitArgs* j9vm_args, IDATA match, char* optionName);
 static void closeAllDLLs (J9JavaVM* vm);
 
@@ -4865,6 +4865,7 @@ registerCmdLineMapping(J9JavaVM* vm, char* sov_option, char* j9_option, UDATA ma
 static IDATA
 registerVMCmdLineMappings(J9JavaVM* vm)
 {
+#if JAVA_SPEC_VERSION < 21
 	char jitOpt[SMALL_STRING_BUF_SIZE];				/* Plenty big enough */
 	char* changeCursor;
 	IDATA bufLeft = 0;
@@ -4873,6 +4874,7 @@ registerVMCmdLineMappings(J9JavaVM* vm)
 	strcpy(jitOpt, SYSPROP_DJAVA_COMPILER_EQUALS);
 	bufLeft = SMALL_STRING_BUF_SIZE - strlen(jitOpt) - 1;
 	changeCursor = &jitOpt[strlen(jitOpt)];
+#endif /* JAVA_SPEC_VERSION < 21 */
 
 #ifdef J9VM_OPT_JVMTI
 	if (registerCmdLineMapping(vm, MAPOPT_JAVAAGENT_COLON, MAPOPT_AGENTLIB_INSTRUMENT_EQUALS, MAP_WITH_INCLUSIVE_OPTIONS) == RC_FAILED) {
@@ -4883,6 +4885,7 @@ registerVMCmdLineMappings(J9JavaVM* vm)
 	if (registerCmdLineMapping(vm, MAPOPT_XCOMP, MAPOPT_XJIT_COUNT0, EXACT_MAP_NO_OPTIONS) == RC_FAILED) {
 		return RC_FAILED;
 	}
+#if JAVA_SPEC_VERSION < 21
 	strncpy(changeCursor, DJCOPT_JITC, bufLeft);
 	if (registerCmdLineMapping(vm, jitOpt, VMOPT_XJIT, EXACT_MAP_NO_OPTIONS) == RC_FAILED) {
 		return RC_FAILED;
@@ -4894,6 +4897,7 @@ registerVMCmdLineMappings(J9JavaVM* vm)
 	if (registerCmdLineMapping(vm, SYSPROP_DJAVA_COMPILER_EQUALS, VMOPT_XINT, STARTSWITH_MAP_NO_OPTIONS) == RC_FAILED) {				/* any other -Djava.compiler= found is mapped to -Xint */
 		return RC_FAILED;
 	}
+#endif /* JAVA_SPEC_VERSION < 21 */
 	if (registerCmdLineMapping(vm, MAPOPT_XDISABLEJAVADUMP, MAPOPT_XDUMP_JAVA_NONE, EXACT_MAP_NO_OPTIONS) == RC_FAILED) {
 		return RC_FAILED;
 	}
@@ -6238,7 +6242,7 @@ testOptionValueOps(J9JavaVM* vm)
 #endif
 
 
-#if (defined(J9VM_OPT_SIDECAR))
+#if defined(J9VM_OPT_SIDECAR) && (JAVA_SPEC_VERSION < 21)
 /* Whine about -Djava.compiler if the option is not used correctly */
 
 static IDATA
@@ -6263,7 +6267,7 @@ checkDjavacompiler(J9PortLibrary *portLibrary, J9VMInitArgs* j9vm_args)
 	}
 	return 0;
 }
-#endif /* J9VM_OPT_SIDECAR */
+#endif /* defined(J9VM_OPT_SIDECAR) && (JAVA_SPEC_VERSION < 21) */
 
 
 static IDATA
@@ -7208,10 +7212,12 @@ protectedInitializeJavaVM(J9PortLibrary* portLibrary, void * userData)
 #endif
 
 #ifdef J9VM_OPT_SIDECAR
+#if JAVA_SPEC_VERSION < 21
 	/* Whine about -Djava.compiler after extra VM options are added, but before mappings are set */
 	if (RC_FAILED == checkDjavacompiler(portLibrary, vm->vmArgsArray)) {
 		goto error;
 	}
+#endif /* JAVA_SPEC_VERSION < 21 */
 
 	if (doParseXlogForCompatibility) {
 		if (JNI_OK != parseXlogForCompatibility(vm)) {
@@ -7367,17 +7373,23 @@ protectedInitializeJavaVM(J9PortLibrary* portLibrary, void * userData)
 		goto error;
 	}
 
-	/* If the JIT started, set the java.compiler system property and allocate the global OSR buffer */
+	/* If the JIT started, set the java.compiler/openj9.compiler system property and allocate the global OSR buffer */
 	if (NULL != vm->jitConfig) {
-		J9VMSystemProperty * property = NULL;
 #ifndef DELETEME
 		UDATA osrGlobalBufferSize = sizeof(J9JITDecompilationInfo);
 #endif
+#if JAVA_SPEC_VERSION < 21
+		J9VMSystemProperty * property = NULL;
 
 		if (J9SYSPROP_ERROR_NONE == getSystemProperty(vm, "java.compiler", &property)) {
 			setSystemProperty(vm, property, J9_JIT_DLL_NAME);
 			property->flags &= ~J9SYSPROP_FLAG_WRITEABLE;
 		}
+#else /* JAVA_SPEC_VERSION < 21 */
+		if (J9SYSPROP_ERROR_NONE != addSystemProperty(vm, "openj9.compiler", J9_JIT_DLL_NAME, 0)) {
+			goto error;
+		}
+#endif /* JAVA_SPEC_VERSION < 21 */
 #ifndef DELETEME
 		osrGlobalBufferSize += ROUND_TO(sizeof(UDATA), vm->jitConfig->osrFramesMaximumSize);
 		osrGlobalBufferSize += ROUND_TO(sizeof(UDATA), vm->jitConfig->osrScratchBufferMaximumSize);
@@ -7422,6 +7434,12 @@ protectedInitializeJavaVM(J9PortLibrary* portLibrary, void * userData)
 		}
 
 	} else {
+#if JAVA_SPEC_VERSION >= 21
+		if (J9SYSPROP_ERROR_NONE != addSystemProperty(vm, "openj9.compiler", "", 0)) {
+			goto error;
+		}
+#endif /* JAVA_SPEC_VERSION >= 21 */
+
 		/* If there is no JIT, change the vm phase so RAS will enable level 2 tracepoints */
 		jvmPhaseChange(vm, J9VM_PHASE_NOT_STARTUP);
 	}
diff --git a/runtime/vm/vmifunc.c b/runtime/vm/vmifunc.c
index 1772ae7f811..e60f0bf8ccd 100644
--- a/runtime/vm/vmifunc.c
+++ b/runtime/vm/vmifunc.c
@@ -204,7 +204,7 @@ vmi_getPortLibrary(VMInterface* vmi)
 <BR>OpenJ9   - 1ca0ab98
 <BR>OMR      - 05d2b8a2
 <BR>JCL      - c2aa0348 based on jdk8u172-b11"</TD></TR>
- * <TR><TD>java.compiler</TD>			<TD>"j9jit29"</TD></TR>
+ * <TR><TD>java.compiler</TD>			<TD>"j9jit29" - not supported from jdk21</TD></TR>
  * <TR><TD>java.class.version</TD>		<TD>"52.0"</TD></TR>
  * <TR><TD>java.home</TD>			<TD>the absolute path of the parent directory of the directory containing the vm
 <BR>i.e. for a vm /clear/bin/vm.exe, java.home is /clear</TD></TR>
diff --git a/runtime/vm/vmprops.c b/runtime/vm/vmprops.c
index 7c4610f982d..4f9800183cc 100644
--- a/runtime/vm/vmprops.c
+++ b/runtime/vm/vmprops.c
@@ -744,11 +744,13 @@ initializeSystemProperties(J9JavaVM * vm)
 	}
 #endif
 
+#if JAVA_SPEC_VERSION < 21
 	/* Don't know the JIT yet, put in a placeholder and make it writeable for now */
 	rc = addSystemProperty(vm, "java.compiler", "", J9SYSPROP_FLAG_WRITEABLE);
 	if (J9SYSPROP_ERROR_NONE != rc) {
 		goto fail;
 	}
+#endif /* JAVA_SPEC_VERSION < 21 */
 
 	/* We don't have enough information yet. Put in placeholders. */
 #if defined(J9VM_OPT_SIDECAR) && !defined(WIN32)
diff --git a/test/functional/Java8andUp/src/org/openj9/test/vmArguments/VmArgumentTests.java b/test/functional/Java8andUp/src/org/openj9/test/vmArguments/VmArgumentTests.java
index 497d4a0d814..c6dd43aff2c 100644
--- a/test/functional/Java8andUp/src/org/openj9/test/vmArguments/VmArgumentTests.java
+++ b/test/functional/Java8andUp/src/org/openj9/test/vmArguments/VmArgumentTests.java
@@ -115,7 +115,7 @@ public class VmArgumentTests {
 	private static final String  MAPOPT_XJIT_COUNT_EQUALS = "-Xjit:count="+MIXED_MODE_THRESHOLD_VALUE;
 
 	private static final String JAVA_COMPILER = "JAVA_COMPILER";
-	private static final String JAVA_COMPILER_VALUE=System.getProperty("java.compiler");
+	private static final String JAVA_COMPILER_VALUE = System.getProperty(VersionCheck.major() < 21 ? "java.compiler" : "openj9.compiler");
 	private static final String SYSPROP_DJAVA_COMPILER_EQUALS = "-Djava.compiler="+JAVA_COMPILER_VALUE;
 
 	private static final boolean isIBM;
@@ -499,7 +499,12 @@ public void testMappedOptions() {
 			env.put(IBM_JAVA_OPTIONS, ibmJavaOptionsArg);
 
 			actualArguments = runAndGetArgumentList(pb);
-			final String[] expectedArguments = new String[] {MAPOPT_XJIT_COUNT_EQUALS, SYSPROP_DJAVA_COMPILER_EQUALS, VMOPT_XRS, ibmJavaOptionsArg};
+			final String[] expectedArguments;
+			if (VersionCheck.major() < 21) {
+				expectedArguments = new String[] {MAPOPT_XJIT_COUNT_EQUALS, SYSPROP_DJAVA_COMPILER_EQUALS, VMOPT_XRS, ibmJavaOptionsArg};
+			} else {
+				expectedArguments = new String[] {MAPOPT_XJIT_COUNT_EQUALS, VMOPT_XRS, ibmJavaOptionsArg};
+			}
 			HashMap<String, Integer> argumentPositions = checkArguments(actualArguments, expectedArguments);
 			checkArgumentSequence(expectedArguments, argumentPositions, true);
 			/* mapped options in environment variables should come before other non-implicit arguments */