diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8d85d50..b7e4395 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -34,6 +34,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - Added a `"rest"` field to parameters. ([#83](https://github.com/webcomponents/custom-elements-manifest/pull/83))
 
+- Added an optional `summary` field to Function and Method return types. ([#109](https://github.com/webcomponents/custom-elements-manifest/pull/109))
+
 <!-- ### Removed -->
 
 ### Fixed
diff --git a/schema.d.ts b/schema.d.ts
index 95e8c76..6f06c0b 100644
--- a/schema.d.ts
+++ b/schema.d.ts
@@ -697,6 +697,15 @@ export interface FunctionLike {
 
   return?: {
     type?: Type;
+
+    /**
+     * A markdown summary suitable for display in a listing.
+     */
+    summary?: string;
+
+    /**
+     * A markdown description.
+     */
     description?: string;
   };
 }
diff --git a/schema.json b/schema.json
index 89a1456..9dd6b5a 100644
--- a/schema.json
+++ b/schema.json
@@ -190,6 +190,11 @@
                 "return": {
                     "properties": {
                         "description": {
+                            "description": "A markdown description.",
+                            "type": "string"
+                        },
+                        "summary": {
+                            "description": "A markdown summary suitable for display in a listing.",
                             "type": "string"
                         },
                         "type": {
@@ -511,6 +516,11 @@
                 "return": {
                     "properties": {
                         "description": {
+                            "description": "A markdown description.",
+                            "type": "string"
+                        },
+                        "summary": {
+                            "description": "A markdown summary suitable for display in a listing.",
                             "type": "string"
                         },
                         "type": {
@@ -633,6 +643,11 @@
                 "return": {
                     "properties": {
                         "description": {
+                            "description": "A markdown description.",
+                            "type": "string"
+                        },
+                        "summary": {
+                            "description": "A markdown summary suitable for display in a listing.",
                             "type": "string"
                         },
                         "type": {
@@ -812,6 +827,11 @@
                 "return": {
                     "properties": {
                         "description": {
+                            "description": "A markdown description.",
+                            "type": "string"
+                        },
+                        "summary": {
+                            "description": "A markdown summary suitable for display in a listing.",
                             "type": "string"
                         },
                         "type": {