diff --git a/core/src/main/java/org/jruby/Ruby.java b/core/src/main/java/org/jruby/Ruby.java
index 9dd148c1cc5..e2830667fa6 100644
--- a/core/src/main/java/org/jruby/Ruby.java
+++ b/core/src/main/java/org/jruby/Ruby.java
@@ -507,13 +507,21 @@ private Ruby(RubyInstanceConfig config) {
         initExceptions(context);
 
         // Thread library utilities
-        mutexClass = Mutex.setup(context, threadClass, objectClass);
-        conditionVariableClass = ConditionVariable.setup(context, threadClass, objectClass);
-        queueClass = Queue.setup(context, threadClass, objectClass);
-        closedQueueError = Queue.setupError(context, queueClass, stopIteration, objectClass);
-        sizedQueueClass = SizedQueue.setup(context, threadClass, queueClass, objectClass);
-
-        fiberClass = new ThreadFiberLibrary().createFiberClass(context, objectClass);
+        if (profile.allowClass("Thread")) {
+            mutexClass = Mutex.setup(context, threadClass, objectClass);
+            conditionVariableClass = ConditionVariable.setup(context, threadClass, objectClass);
+            queueClass = Queue.setup(context, threadClass, objectClass);
+            closedQueueError = Queue.setupError(context, queueClass, stopIteration, objectClass);
+            sizedQueueClass = SizedQueue.setup(context, threadClass, queueClass, objectClass);
+            fiberClass = new ThreadFiberLibrary().createFiberClass(context, objectClass);
+        } else {
+            mutexClass = null;
+            conditionVariableClass = null;
+            queueClass = null;
+            closedQueueError = null;
+            sizedQueueClass = null;
+            fiberClass = null;
+        }
 
         dataClass = RubyData.createDataClass(context, objectClass);
 
@@ -1676,12 +1684,12 @@ private void initExceptions(ThreadContext context) {
         ifAllowed("KeyError",               (ruby) -> keyError = RubyKeyError.define(context, indexError));
         ifAllowed("DomainError",            (ruby) -> mathDomainError = RubyDomainError.define(context, argumentError, mathModule));
 
-        setRegexpTimeoutError(regexpClass.defineClassUnder(context, "TimeoutError", getRegexpError(), RubyRegexpError::new));
+        ifAllowed("Regex",                  (ruby) -> setRegexpTimeoutError(regexpClass.defineClassUnder(context, "TimeoutError", getRegexpError(), RubyRegexpError::new)));
 
         RubyClass runtimeError = this.runtimeError;
-        ObjectAllocator runtimeErrorAllocator = runtimeError.getAllocator();
 
-        if (Options.FIBER_SCHEDULER.load()) {
+        if (profile.allowClass("Thread") && Options.FIBER_SCHEDULER.load()) {
+            ObjectAllocator runtimeErrorAllocator = runtimeError.getAllocator();
             bufferLockedError = ioBufferClass.defineClassUnder(context, "LockedError", runtimeError, runtimeErrorAllocator);
             bufferAllocationError = ioBufferClass.defineClassUnder(context, "AllocationError", runtimeError, runtimeErrorAllocator);
             bufferAccessError = ioBufferClass.defineClassUnder(context, "AccessError", runtimeError, runtimeErrorAllocator);
@@ -1775,7 +1783,9 @@ private void initJavaSupport(ThreadContext context) {
 
     private void initRubyKernel() {
         // load Ruby parts of core
-        loadService.loadFromClassLoader(getClassLoader(), "jruby/kernel.rb", false);
+        if (profile.allowLoad("jruby/kernel")) {
+            loadService.loadFromClassLoader(getClassLoader(), "jruby/kernel.rb", false);
+        }
     }
 
     private void initRubyPreludes() {
@@ -1783,7 +1793,9 @@ private void initRubyPreludes() {
         if (RubyInstanceConfig.DEBUG_PARSER) return;
 
         // load Ruby parts of core
-        loadService.loadFromClassLoader(getClassLoader(), "jruby/preludes.rb", false);
+        if (profile.allowLoad("jruby/preludes")) {
+            loadService.loadFromClassLoader(getClassLoader(), "jruby/preludes.rb", false);
+        }
     }
 
     public IRManager getIRManager() {
diff --git a/core/src/main/java/org/jruby/RubyGlobal.java b/core/src/main/java/org/jruby/RubyGlobal.java
index 2e58c1c9810..6ef275d5b7e 100644
--- a/core/src/main/java/org/jruby/RubyGlobal.java
+++ b/core/src/main/java/org/jruby/RubyGlobal.java
@@ -199,7 +199,9 @@ public static RubyHash createGlobalsAndENV(ThreadContext context, GlobalVariable
         runtime.defineVariable(new LastlineGlobalVariable(runtime, "$_"), FRAME);
         runtime.defineVariable(new LastExitStatusVariable(runtime, "$?"), THREAD);
 
-        runtime.defineVariable(new ErrorInfoGlobalVariable(runtime, "$!", context.nil), THREAD);
+        if (runtime.getProfile().allowClass("Thread")) {
+            runtime.defineVariable(new ErrorInfoGlobalVariable(runtime, "$!", context.nil), THREAD);
+        }
         runtime.defineVariable(new NonEffectiveGlobalVariable(runtime, "$=", context.fals), GLOBAL);
 
         if(instanceConfig.getInputFieldSeparator() == null) {
diff --git a/core/src/test/java/org/jruby/javasupport/JavaEmbedUtilsTest.java b/core/src/test/java/org/jruby/javasupport/JavaEmbedUtilsTest.java
index ce4bf4c39d6..116159378a0 100644
--- a/core/src/test/java/org/jruby/javasupport/JavaEmbedUtilsTest.java
+++ b/core/src/test/java/org/jruby/javasupport/JavaEmbedUtilsTest.java
@@ -13,9 +13,15 @@
 import static org.jruby.api.Create.newEmptyArray;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertSame;
+import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
+import org.jruby.Profile;
+import org.jruby.RubyFixnum;
+import org.jruby.RubyString;
+import org.jruby.exceptions.NameError;
+import org.jruby.exceptions.SyntaxError;
 import org.jruby.java.proxies.ConcreteJavaProxy;
 import org.jruby.java.proxies.JavaProxy;
 import org.jruby.runtime.ThreadContext;
@@ -64,6 +70,55 @@ public void testAddClassloaderToLoadPathOnTCCL() throws Exception {
         assertEquals(result, "uri:" + url);
     }
 
+    class CustomProfile implements Profile {
+        private List classAllow = List.of("String", "Fixnum", "Integer", "Numeric", "Hash", "Array",
+                "Thread", "ThreadGroup", "RubyError", "StopIteration", "LoadError", "ArgumentError", "Encoding",
+                "EncodingError", "StandardError", "Exception", "NameError", "SyntaxError", "ScriptError");
+        private List loadAllow = List.of("jruby/java.rb", "jruby/java/core_ext.rb", "jruby/java/java_ext.rb",
+                "jruby/java/core_ext/object.rb");
+
+        @Override
+        public boolean allowBuiltin(String name) {
+            return false;
+        }
+
+        @Override
+        public boolean allowClass(String name) {
+            return classAllow.contains(name);
+        }
+
+        @Override
+        public boolean allowModule(String name) {
+            return false;
+        }
+
+        @Override
+        public boolean allowLoad(String name) {
+            return loadAllow.contains(name);
+        }
+
+        @Override
+        public boolean allowRequire(String name) {
+            return false;
+        }
+    }
+
+    @Test
+    public void testRestrictedProfile() throws Exception {
+        RubyInstanceConfig config = new RubyInstanceConfig();
+        config.setDisableGems(true);
+        config.setProfile(new CustomProfile());
+
+        Ruby runtime = Ruby.newInstance(config);
+        assertEquals(20L, ((RubyFixnum) runtime.evalScriptlet("def double(a); a * 2; end; double(10)")).getValue());
+        assertThrows(NameError.class, () -> runtime.evalScriptlet("File.open('test.tmp')"));
+        assertThrows(NameError.class, () -> runtime.evalScriptlet("UDPSocket.new"));
+        assertEquals("cute_cats",((RubyString)runtime.evalScriptlet("\"cute_cats\"")).getValue());
+        assertEquals("cute_cat",((RubyString)runtime.evalScriptlet("\"cute_cats\".delete('s')")).getValue());
+        assertThrows(SyntaxError.class, () -> runtime.evalScriptlet("puts 'you shouldn't see this'"));
+        //assertThrows(NameError.class, () -> runtime.evalScriptlet("IO.sysopen('test.tmp')"));
+    }
+
     @Test
     public void testAddClassloaderToLoadPathOnNoneTCCL() throws Exception {
         RubyInstanceConfig config = new RubyInstanceConfig();