diff --git a/httpclient5/src/main/java/org/apache/hc/client5/http/cookie/Cookie.java b/httpclient5/src/main/java/org/apache/hc/client5/http/cookie/Cookie.java
index 3782a51131..25d7293b58 100644
--- a/httpclient5/src/main/java/org/apache/hc/client5/http/cookie/Cookie.java
+++ b/httpclient5/src/main/java/org/apache/hc/client5/http/cookie/Cookie.java
@@ -45,7 +45,7 @@ public interface Cookie {
     String MAX_AGE_ATTR = "max-age";
     String SECURE_ATTR = "secure";
     String EXPIRES_ATTR = "expires";
-    String HTTP_ONLY_ATTR = "httpOnly";
+    String HTTP_ONLY_ATTR = "httponly";
 
     /**
      * @since 5.0
diff --git a/httpclient5/src/test/java/org/apache/hc/client5/http/impl/cookie/TestRFC6265CookieSpec.java b/httpclient5/src/test/java/org/apache/hc/client5/http/impl/cookie/TestRFC6265CookieSpec.java
index 945938cf14..6bb9ad14f6 100644
--- a/httpclient5/src/test/java/org/apache/hc/client5/http/impl/cookie/TestRFC6265CookieSpec.java
+++ b/httpclient5/src/test/java/org/apache/hc/client5/http/impl/cookie/TestRFC6265CookieSpec.java
@@ -202,6 +202,19 @@ void testParseCookieWithAttributes3() throws Exception {
         Assertions.assertEquals("", cookie.getAttribute("p1"));
     }
 
+    @Test
+    void testParseCookieWithHttpOnly() throws Exception {
+        final RFC6265CookieSpec cookiespec = new RFC6265CookieSpec();
+
+        final Header header = new BasicHeader("Set-Cookie", "name = value ; HttpOnly");
+        final CookieOrigin origin = new CookieOrigin("host", 80, "/path/", true);
+        final List<Cookie> cookies = cookiespec.parse(header, origin);
+
+        Assertions.assertEquals(1, cookies.size());
+        final Cookie cookie = cookies.get(0);
+        Assertions.assertTrue(cookie.containsAttribute(Cookie.HTTP_ONLY_ATTR));
+    }
+
     @Test
     void testValidateCookieBasics() throws Exception {
         final CommonCookieAttributeHandler h1 = Mockito.mock(CommonCookieAttributeHandler.class);