diff --git a/components/lib/dropdown/DropdownBase.js b/components/lib/dropdown/DropdownBase.js
index 3581003613..2230add1d2 100644
--- a/components/lib/dropdown/DropdownBase.js
+++ b/components/lib/dropdown/DropdownBase.js
@@ -20,7 +20,10 @@ const classes = {
               }),
     trigger: 'p-dropdown-trigger',
     emptyMessage: 'p-dropdown-empty-message',
-    itemGroup: 'p-dropdown-item-group',
+    itemGroup: ({ optionGroupLabel }) =>
+        classNames('p-dropdown-item-group', {
+            'p-dropdown-item-empty': !optionGroupLabel || optionGroupLabel.length === 0
+        }),
     dropdownIcon: 'p-dropdown-trigger-icon p-clickable',
     clearIcon: 'p-dropdown-clear-icon p-clickable',
     filterIcon: 'p-dropdown-filter-icon',
diff --git a/components/lib/dropdown/DropdownPanel.js b/components/lib/dropdown/DropdownPanel.js
index 3e4a8cc34a..0009205c5f 100644
--- a/components/lib/dropdown/DropdownPanel.js
+++ b/components/lib/dropdown/DropdownPanel.js
@@ -98,12 +98,13 @@ export const DropdownPanel = React.memo(
             style = { ...style, ...option.style };
 
             if (props.optionGroupLabel) {
+                const { optionGroupLabel } = props;
                 const groupContent = props.optionGroupTemplate ? ObjectUtils.getJSXElement(props.optionGroupTemplate, option, index) : props.getOptionGroupLabel(option);
                 const groupChildrenContent = createGroupChildren(option, style);
                 const key = index + '_' + props.getOptionGroupRenderKey(option);
                 const itemGroupProps = mergeProps(
                     {
-                        className: cx('itemGroup'),
+                        className: cx('itemGroup', { optionGroupLabel }),
                         style
                     },
                     getPTOptions('itemGroup')