diff --git a/CHANGELOG.md b/CHANGELOG.md
index 38a5a0a..e4c5983 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@
 ### Improvements
 * Parse timestamps as `ZonedDateTime` instead of `String` representation
 * Remove redundant `java.base` requirement from _module-info.java_ (#69)
+* Close Java HTTP Client when running on Java 21 or later (#70)
 
 ### Dependencies
 * Updated Jackson to 2.16.0
diff --git a/src/main/java/de/stklcode/jvault/connector/internal/RequestHelper.java b/src/main/java/de/stklcode/jvault/connector/internal/RequestHelper.java
index ec047dc..1cd4847 100644
--- a/src/main/java/de/stklcode/jvault/connector/internal/RequestHelper.java
+++ b/src/main/java/de/stklcode/jvault/connector/internal/RequestHelper.java
@@ -363,6 +363,15 @@ public final class RequestHelper implements Serializable {
             }
         } catch (CompletionException e) {
             throw new ConnectionException(Error.CONNECTION, e.getCause());
+        } finally {
+            if (client instanceof AutoCloseable) {
+                // Close the client, which is supported since JDK21.
+                try {
+                    ((AutoCloseable) client).close();
+                } catch (Exception ignored) {
+                    // Ignore
+                }
+            }
         }
     }