diff --git a/packages/github/RELEASES.md b/packages/github/RELEASES.md
index b56ec46549..00db5e66f1 100644
--- a/packages/github/RELEASES.md
+++ b/packages/github/RELEASES.md
@@ -1,5 +1,9 @@
 # @actions/github Releases
 
+### 2.2.0
+
+- [Support GHES: Use GITHUB_API_URL and GITHUB_GRAPHQL_URL to determine baseUrl](https://github.com/actions/toolkit/pull/449)
+
 ### 2.1.1
 
 - [Use import {Octokit}](https://github.com/actions/toolkit/pull/332)
diff --git a/packages/github/package-lock.json b/packages/github/package-lock.json
index 34a0a94afb..a075eac212 100644
--- a/packages/github/package-lock.json
+++ b/packages/github/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "@actions/github",
-  "version": "2.1.1",
+  "version": "2.2.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/packages/github/package.json b/packages/github/package.json
index 45582ccc41..ef58523ba6 100644
--- a/packages/github/package.json
+++ b/packages/github/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@actions/github",
-  "version": "2.1.1",
+  "version": "2.2.0",
   "description": "Actions github lib",
   "keywords": [
     "github",
diff --git a/packages/github/src/github.ts b/packages/github/src/github.ts
index 515f3700c1..699998dc69 100644
--- a/packages/github/src/github.ts
+++ b/packages/github/src/github.ts
@@ -61,6 +61,9 @@ export class GitHub extends Octokit {
     const token = args[0]
     const options = {...args[1]} // Shallow clone - don't mutate the object provided by the caller
 
+    // Base URL - GHES or Dotcom
+    options.baseUrl = options.baseUrl || this.getApiBaseUrl()
+
     // Auth
     const auth = GitHub.getAuthString(token, options)
     if (auth) {
@@ -68,7 +71,7 @@ export class GitHub extends Octokit {
     }
 
     // Proxy
-    const agent = GitHub.getProxyAgent(options)
+    const agent = GitHub.getProxyAgent(options.baseUrl, options)
     if (agent) {
       // Shallow clone - don't mutate the object provided by the caller
       options.request = options.request ? {...options.request} : {}
@@ -82,6 +85,7 @@ export class GitHub extends Octokit {
 
   private static getGraphQL(args: [string, Octokit.Options]): GraphQL {
     const defaults: GraphQLRequestParameters = {}
+    defaults.baseUrl = this.getGraphQLBaseUrl()
     const token = args[0]
     const options = args[1]
 
@@ -94,7 +98,7 @@ export class GitHub extends Octokit {
     }
 
     // Proxy
-    const agent = GitHub.getProxyAgent(options)
+    const agent = GitHub.getProxyAgent(defaults.baseUrl, options)
     if (agent) {
       defaults.request = {agent}
     }
@@ -119,16 +123,36 @@ export class GitHub extends Octokit {
   }
 
   private static getProxyAgent(
+    destinationUrl: string,
     options: Octokit.Options
   ): http.Agent | undefined {
     if (!options.request?.agent) {
-      const serverUrl = 'https://api.github.com'
-      if (httpClient.getProxyUrl(serverUrl)) {
+      if (httpClient.getProxyUrl(destinationUrl)) {
         const hc = new httpClient.HttpClient()
-        return hc.getAgent(serverUrl)
+        return hc.getAgent(destinationUrl)
       }
     }
 
     return undefined
   }
+
+  private static getApiBaseUrl(): string {
+    return process.env['GITHUB_API_URL'] || 'https://api.github.com'
+  }
+
+  private static getGraphQLBaseUrl(): string {
+    let url =
+      process.env['GITHUB_GRAPHQL_URL'] || 'https://api.github.com/graphql'
+
+    // Shouldn't be a trailing slash, but remove if so
+    if (url.endsWith('/')) {
+      url = url.substr(0, url.length - 1)
+    }
+
+    // Remove trailing "/graphql"
+    if (url.toUpperCase().endsWith('/GRAPHQL')) {
+      url = url.substr(0, url.length - '/graphql'.length)
+    }
+    return url
+  }
 }