diff --git a/src/apis/index.js b/src/apis/index.js
index 940cc8d86..442ca049f 100644
--- a/src/apis/index.js
+++ b/src/apis/index.js
@@ -136,6 +136,7 @@ import selectThumbnailPages from './selectThumbnailPages';
 import unselectThumbnailPages from './unselectThumbnailPages';
 import setSearchResults from './setSearchResults';
 import setActiveResult from './setActiveResult';
+import setAnnotationContentOverlayHandler from './setAnnotationContentOverlayHandler';
 
 export default store => {
   window.readerControl = {
@@ -217,6 +218,7 @@ export default store => {
     getSelectedThumbnailPageNumbers: getSelectedThumbnailPageNumbers(store),
     selectThumbnailPages: selectThumbnailPages(store),
     unselectThumbnailPages: unselectThumbnailPages(store),
+    setAnnotationContentOverlayHandler: setAnnotationContentOverlayHandler(store),
 
     // undocumented and deprecated, to be removed in 7.0
     closeElement: closeElement(store),
diff --git a/src/apis/setAnnotationContentOverlayHandler.js b/src/apis/setAnnotationContentOverlayHandler.js
new file mode 100644
index 000000000..14edfba8c
--- /dev/null
+++ b/src/apis/setAnnotationContentOverlayHandler.js
@@ -0,0 +1,22 @@
+import action from 'actions';
+
+/**
+ * Adds a custom overlay to annotations on mouseHover, overriding the existing overlay.
+ * @method WebViewerInstance#setAnnotationContentOverlayHandler
+ * @param {function} customOverlayHandler a function that takes an annotation and returns a DOM Element, which is rendered as a tooltip when hovering over the annotation
+ *  * @example
+WebViewer(...)
+  .then(function(instance) {
+    instance.setAnnotationContentOverlayHandler(annotation => {
+        const div = document.createElement('div');
+        div.appendChild(document.createTextNode(`Created by: ${annotation.Author}`));
+        div.appendChild(document.createElement('br'));
+        div.appendChild(document.createTextNode(`Created on ${annotation.DateCreated}`));
+        return div;
+    });
+  });
+ */
+
+export default store => annotationContentOverlayHandler => {
+  store.dispatch(action.setAnnotationContentOverlayHandler(annotationContentOverlayHandler));
+};
\ No newline at end of file
diff --git a/src/components/AnnotationContentOverlay/AnnotationContentOverlay.js b/src/components/AnnotationContentOverlay/AnnotationContentOverlay.js
index 38a9bc814..c6db1b813 100644
--- a/src/components/AnnotationContentOverlay/AnnotationContentOverlay.js
+++ b/src/components/AnnotationContentOverlay/AnnotationContentOverlay.js
@@ -1,3 +1,4 @@
+/* eslint-disable react/prop-types */
 import React, { useState, useEffect } from 'react';
 import { useSelector } from 'react-redux';
 import { useTranslation } from 'react-i18next';
@@ -8,6 +9,8 @@ import selectors from 'selectors';
 
 import './AnnotationContentOverlay.scss';
 
+import CustomElement from '../CustomElement';
+
 const MAX_CHARACTERS = 100;
 
 const AnnotationContentOverlay = () => {
@@ -21,6 +24,13 @@ const AnnotationContentOverlay = () => {
     top: 0,
   });
 
+  // Clients have the option to customize how the tooltip is rendered
+  // by passing a handler
+  const customHandler = useSelector(state =>
+    selectors.getAnnotationContentOverlayHandler(state),
+  );
+  const isUsingCustomHandler = customHandler !== null;
+
   useEffect(() => {
     const onMouseHover = e => {
       const viewElement = core.getViewerElement();
@@ -55,25 +65,58 @@ const AnnotationContentOverlay = () => {
   const contents = annotation?.getContents();
   const numberOfReplies = annotation?.getReplies().length;
 
-  return isDisabled || isMobileDevice || !contents ? null : (
+  const OverlayWrapper = props => (
     <div
       className="Overlay AnnotationContentOverlay"
       data-element="annotationContentOverlay"
       style={{ ...overlayPosition }}
     >
-      <div className="author">{core.getDisplayAuthor(annotation)}</div>
-      <div className="contents">
-        {contents.length > MAX_CHARACTERS
-          ? `${contents.slice(0, MAX_CHARACTERS)}...`
-          : contents}
-      </div>
-      {numberOfReplies > 0 && (
-        <div className="replies">
-          {t('message.annotationReplyCount', { count: numberOfReplies })}
-        </div>
-      )}
+      {props.children}
     </div>
   );
+
+  const CustomOverlay = () => {
+    if (annotation) {
+      return (
+        <OverlayWrapper>
+          <CustomElement render={() => customHandler(annotation)} />
+        </OverlayWrapper>
+      );
+    } else {
+      return null;
+    }
+  };
+
+  const DefaultOverlay = () => {
+    if (contents) {
+      return (
+        <OverlayWrapper>
+          <div className="author">{core.getDisplayAuthor(annotation)}</div>
+          <div className="contents">
+            {contents.length > MAX_CHARACTERS
+              ? `${contents.slice(0, MAX_CHARACTERS)}...`
+              : contents}
+          </div>
+          {numberOfReplies > 0 && (
+            <div className="replies">
+              {t('message.annotationReplyCount', { count: numberOfReplies })}
+            </div>
+          )}
+        </OverlayWrapper>
+      );
+    } else {
+      return null;
+    }
+  };
+
+  if (isDisabled || isMobileDevice) {
+    return null;
+  } else if (isUsingCustomHandler) {
+    return <CustomOverlay />;
+  } else {
+    return <DefaultOverlay />;
+  }
+
 };
 
 export default AnnotationContentOverlay;
diff --git a/src/redux/actions/exposedActions.js b/src/redux/actions/exposedActions.js
index ca892f34c..7cc8dd09c 100644
--- a/src/redux/actions/exposedActions.js
+++ b/src/redux/actions/exposedActions.js
@@ -245,4 +245,8 @@ export const setActiveResult = (activeResult, index) => ({
 export const setActiveResultIndex = index => ({
   type: 'SET_ACTIVE_RESULT_INDEX',
   payload: { index },
-});
\ No newline at end of file
+});
+export const setAnnotationContentOverlayHandler = annotationContentOverlayHandler => ({
+  type: 'SET_ANNOTATION_CONTENT_OVERLAY_HANDLER',
+  payload: { annotationContentOverlayHandler }
+});
diff --git a/src/redux/initialState.js b/src/redux/initialState.js
index cf4b5287b..2cefdfe1f 100644
--- a/src/redux/initialState.js
+++ b/src/redux/initialState.js
@@ -209,6 +209,9 @@ export default {
     userData: [],
     customMeasurementOverlay: [],
     noteTransformFunction: null,
+    savedSignatures: [],
+    selectedSignatureIndex: 0,
+    annotationContentOverlayHandler: null,
   },
   search: {
     listeners: [],
diff --git a/src/redux/reducers/viewerReducer.js b/src/redux/reducers/viewerReducer.js
index 8428ee77f..39716afda 100644
--- a/src/redux/reducers/viewerReducer.js
+++ b/src/redux/reducers/viewerReducer.js
@@ -232,6 +232,8 @@ export default initialState => (state = initialState, action) => {
       return { ...state, customElementOverrides: { ...state.customElementOverrides, [payload.dataElement]: payload.overrides } };
     case 'SET_NOTE_TRANSFORM_FUNCTION':
       return { ...state, noteTransformFunction: payload.noteTransformFunction };
+    case 'SET_ANNOTATION_CONTENT_OVERLAY_HANDLER':
+      return { ...state, annotationContentOverlayHandler: payload.annotationContentOverlayHandler };
     default:
       return state;
   }
diff --git a/src/redux/selectors/exposedSelectors.js b/src/redux/selectors/exposedSelectors.js
index 1a5be3f8b..bdd9e6cb6 100644
--- a/src/redux/selectors/exposedSelectors.js
+++ b/src/redux/selectors/exposedSelectors.js
@@ -145,6 +145,8 @@ export const getAllowPageNavigation = state => state.viewer.allowPageNavigation;
 
 export const getCustomMeasurementOverlay = state => state.viewer.customMeasurementOverlay;
 
+export const getAnnotationContentOverlayHandler = state => state.viewer.annotationContentOverlayHandler;
+
 // warning message
 export const getWarningMessage = state => state.viewer.warning?.message || '';