diff --git a/jetty-util/src/main/java/org/eclipse/jetty/util/thread/ReservedThreadExecutor.java b/jetty-util/src/main/java/org/eclipse/jetty/util/thread/ReservedThreadExecutor.java
index ef59ff2a6f8..3941107d648 100644
--- a/jetty-util/src/main/java/org/eclipse/jetty/util/thread/ReservedThreadExecutor.java
+++ b/jetty-util/src/main/java/org/eclipse/jetty/util/thread/ReservedThreadExecutor.java
@@ -282,7 +282,7 @@ public class ReservedThreadExecutor extends AbstractLifeCycle implements TryExec
             {
                 LOG.ignore(e);
                 _size.getAndIncrement();
-                _stack.addFirst(this);
+                _stack.offerFirst(this);
                 return false;
             }
         }
@@ -307,14 +307,13 @@ public class ReservedThreadExecutor extends AbstractLifeCycle implements TryExec
                     if (task != null)
                         return task;
 
-                    // Because threads are held in a stack, excess threads will be
-                    // idle.  However, we cannot remove threads from the bottom of
-                    // the stack, so we submit a poison pill job to stop the thread
-                    // on top of the stack (which unfortunately will be the most
-                    // recently used)
-                    if (LOG.isDebugEnabled())
-                        LOG.debug("{} IDLE", this);
-                    tryExecute(STOP);
+                    if (_stack.remove(this))
+                    {
+                        if (LOG.isDebugEnabled())
+                            LOG.debug("{} IDLE", this);
+                        _size.decrementAndGet();
+                        return STOP;
+                    }
                 }
                 catch (InterruptedException e)
                 {
diff --git a/jetty-util/src/test/java/org/eclipse/jetty/util/thread/ReservedThreadExecutorTest.java b/jetty-util/src/test/java/org/eclipse/jetty/util/thread/ReservedThreadExecutorTest.java
index f30f300a1ad..a68e5992388 100644
--- a/jetty-util/src/test/java/org/eclipse/jetty/util/thread/ReservedThreadExecutorTest.java
+++ b/jetty-util/src/test/java/org/eclipse/jetty/util/thread/ReservedThreadExecutorTest.java
@@ -32,6 +32,8 @@ import org.junit.jupiter.api.Test;
 
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.is;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assertions.fail;
 
@@ -183,6 +185,26 @@ public class ReservedThreadExecutorTest
         assertThat(_reservedExecutor.getAvailable(), is(0));
     }
 
+    @Test
+    public void testReservedIdleTimeoutWithOneReservedThread() throws Exception
+    {
+        long idleTimeout = 500;
+        _reservedExecutor.stop();
+        _reservedExecutor.setIdleTimeout(idleTimeout, TimeUnit.MILLISECONDS);
+        _reservedExecutor.start();
+
+        assertThat(_reservedExecutor.tryExecute(NOOP), is(false));
+        Thread thread = _executor.startThread();
+        assertNotNull(thread);
+        waitForAvailable(1);
+
+        Thread.sleep(2 * idleTimeout);
+
+        waitForAvailable(0);
+        thread.join(2 * idleTimeout);
+        assertFalse(thread.isAlive());
+    }
+
     protected void waitForAvailable(int size) throws InterruptedException
     {
         long started = System.nanoTime();
@@ -211,11 +233,16 @@ public class ReservedThreadExecutorTest
             _queue.addLast(task);
         }
 
-        public void startThread()
+        public Thread startThread()
         {
             Runnable task = _queue.pollFirst();
             if (task != null)
-                new Thread(task).start();
+            {
+                Thread thread = new Thread(task);
+                thread.start();
+                return thread;
+            }
+            return null;
         }
     }