diff --git a/CHANGELOG.md b/CHANGELOG.md
index 517d3540ae9..472c468766f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,6 @@
 ## [`master`](https://github.com/elastic/eui/tree/master)
 
+- Added `loading` icon to `EuiComboBox` input when `isLoading` is `true` ([#4015](https://github.com/elastic/eui/pull/4015))
 - Changed `value` prop in `EuiExpression` to not required ([#4014](https://github.com/elastic/eui/pull/4014))
 - Added `fold` and `unfold` glyphs to `EuiIcon` ([#3994](https://github.com/elastic/eui/pull/3994))
 
diff --git a/src/components/combo_box/_combo_box.scss b/src/components/combo_box/_combo_box.scss
index 700dd892c8c..ee7e0357329 100644
--- a/src/components/combo_box/_combo_box.scss
+++ b/src/components/combo_box/_combo_box.scss
@@ -4,7 +4,7 @@
 
   /**
    * 1. Allow pills to truncate their text with an ellipsis.
-   * 2. Don't allow pills to overlap with the caret or clear button.
+   * 2. Don't allow pills to overlap with the caret, loading icon or clear button.
    * 3. The height on combo can be larger than normal text inputs.
    */
 
@@ -48,6 +48,14 @@
     &.euiComboBox__inputWrap-isClearable {
       @include euiFormControlLayoutPadding(2); /* 2 */
     }
+
+    &.euiComboBox__inputWrap-isLoading {
+      @include euiFormControlLayoutPadding(2); /* 2 */
+    }
+
+    &.euiComboBox__inputWrap-isLoading.euiComboBox__inputWrap-isClearable {
+      @include euiFormControlLayoutPadding(3); /* 2 */
+    }
   }
 
   /**
@@ -110,6 +118,14 @@
       &.euiComboBox__inputWrap-isClearable {
         @include euiFormControlLayoutPadding(2, $compressed: true); /* 2 */
       }
+
+      &.euiComboBox__inputWrap-isLoading {
+        @include euiFormControlLayoutPadding(2, $compressed: true); /* 2 */
+      }
+
+      &.euiComboBox__inputWrap-isLoading.euiComboBox__inputWrap-isClearable {
+        @include euiFormControlLayoutPadding(3, $compressed: true); /* 2 */
+      }
     }
   }
 }
diff --git a/src/components/combo_box/combo_box.tsx b/src/components/combo_box/combo_box.tsx
index c892d42ae16..79717a18173 100644
--- a/src/components/combo_box/combo_box.tsx
+++ b/src/components/combo_box/combo_box.tsx
@@ -1051,6 +1051,7 @@ export class EuiComboBox<T> extends Component<
           value={value}
           append={singleSelection ? append : undefined}
           prepend={singleSelection ? prepend : undefined}
+          isLoading={isLoading}
         />
         {optionsList}
       </div>
diff --git a/src/components/combo_box/combo_box_input/combo_box_input.tsx b/src/components/combo_box/combo_box_input/combo_box_input.tsx
index 053feb0c0f1..77f44fccb1d 100644
--- a/src/components/combo_box/combo_box_input/combo_box_input.tsx
+++ b/src/components/combo_box/combo_box_input/combo_box_input.tsx
@@ -71,6 +71,7 @@ export interface EuiComboBoxInputProps<T> extends CommonProps {
   value?: string;
   prepend?: EuiFormControlLayoutProps['prepend'];
   append?: EuiFormControlLayoutProps['append'];
+  isLoading?: boolean;
 }
 
 interface EuiComboBoxInputState {
@@ -157,6 +158,7 @@ export class EuiComboBoxInput<T> extends Component<
       value,
       prepend,
       append,
+      isLoading,
     } = this.props;
 
     const singleSelection = Boolean(singleSelectionProp);
@@ -261,6 +263,7 @@ export class EuiComboBoxInput<T> extends Component<
       'euiComboBox__inputWrap--compressed': compressed,
       'euiComboBox__inputWrap--fullWidth': fullWidth,
       'euiComboBox__inputWrap--noWrap': singleSelection,
+      'euiComboBox__inputWrap-isLoading': isLoading,
       'euiComboBox__inputWrap-isClearable': onClear,
       'euiComboBox__inputWrap--inGroup': prepend || append,
     });
@@ -269,6 +272,7 @@ export class EuiComboBoxInput<T> extends Component<
       <EuiFormControlLayout
         icon={icon}
         {...clickProps}
+        isLoading={isLoading}
         compressed={compressed}
         fullWidth={fullWidth}
         prepend={prepend}