diff --git a/httpclient5/src/main/java/org/apache/hc/client5/http/impl/async/AbstractHttpAsyncClientBase.java b/httpclient5/src/main/java/org/apache/hc/client5/http/impl/async/AbstractHttpAsyncClientBase.java
index 264faa2c70..9890f7712a 100644
--- a/httpclient5/src/main/java/org/apache/hc/client5/http/impl/async/AbstractHttpAsyncClientBase.java
+++ b/httpclient5/src/main/java/org/apache/hc/client5/http/impl/async/AbstractHttpAsyncClientBase.java
@@ -29,6 +29,7 @@
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicReference;
 
 import org.apache.hc.core5.function.Supplier;
@@ -116,7 +117,18 @@ public final void close(final CloseMode closeMode) {
         }
         ioReactor.initiateShutdown();
         ioReactor.close(closeMode);
-        executorService.shutdownNow();
+        if (closeMode == CloseMode.GRACEFUL) {
+            executorService.shutdown();
+            try {
+                if (!executorService.awaitTermination(1, TimeUnit.SECONDS)) {
+                    executorService.shutdownNow();
+                }
+            } catch (final InterruptedException ignore) {
+                Thread.currentThread().interrupt();
+            }
+        } else {
+            executorService.shutdownNow();
+        }
         internalClose(closeMode);
     }