diff --git a/lib/browser/api/app.js b/lib/browser/api/app.js
index 66f6ae651acf1..b237638657518 100644
--- a/lib/browser/api/app.js
+++ b/lib/browser/api/app.js
@@ -107,21 +107,6 @@ for (let name of events) {
   })
 }
 
-// TODO(MarshallOfSound): Remove in 4.0
-app.releaseSingleInstance = () => {
-  deprecate.warn('app.releaseSingleInstance(cb)', 'app.releaseSingleInstanceLock()')
-  app.releaseSingleInstanceLock()
-}
-
-// TODO(MarshallOfSound): Remove in 4.0
-app.makeSingleInstance = (oldStyleFn) => {
-  deprecate.warn('app.makeSingleInstance(cb)', 'app.requestSingleInstanceLock() and app.on(\'second-instance\', cb)')
-  if (oldStyleFn && typeof oldStyleFn === 'function') {
-    app.on('second-instance', (event, ...args) => oldStyleFn(...args))
-  }
-  return !app.requestSingleInstanceLock()
-}
-
 // Wrappers for native classes.
 const {DownloadItem} = process.atomBinding('download_item')
 Object.setPrototypeOf(DownloadItem.prototype, EventEmitter.prototype)
diff --git a/spec/api-app-spec.js b/spec/api-app-spec.js
index e341f7efa7800..c6333bba1adae 100644
--- a/spec/api-app-spec.js
+++ b/spec/api-app-spec.js
@@ -202,28 +202,6 @@ describe('app module', () => {
     })
   })
 
-  // TODO(MarshallOfSound) - Remove in 4.0.0
-  describe('app.makeSingleInstance', () => {
-    it('prevents the second launch of app', function (done) {
-      this.timeout(120000)
-      const appPath = path.join(__dirname, 'fixtures', 'api', 'singleton-old')
-      // First launch should exit with 0.
-      const first = ChildProcess.spawn(remote.process.execPath, [appPath])
-      first.once('exit', code => {
-        expect(code).to.equal(0)
-      })
-      // Start second app when received output.
-      first.stdout.once('data', () => {
-        // Second launch should exit with 1.
-        const second = ChildProcess.spawn(remote.process.execPath, [appPath])
-        second.once('exit', code => {
-          expect(code).to.equal(1)
-          done()
-        })
-      })
-    })
-  })
-
   describe('app.requestSingleInstanceLock', () => {
     it('prevents the second launch of app', function (done) {
       this.timeout(120000)
diff --git a/spec/fixtures/api/singleton-old/main.js b/spec/fixtures/api/singleton-old/main.js
deleted file mode 100644
index ef7fa7b05f55c..0000000000000
--- a/spec/fixtures/api/singleton-old/main.js
+++ /dev/null
@@ -1,13 +0,0 @@
-const {app} = require('electron')
-
-app.once('ready', () => {
-  console.log('started')  // ping parent
-})
-
-const shouldExit = app.makeSingleInstance(() => {
-  setImmediate(() => app.exit(0))
-})
-
-if (shouldExit) {
-  app.exit(1)
-}
diff --git a/spec/fixtures/api/singleton-old/package.json b/spec/fixtures/api/singleton-old/package.json
deleted file mode 100644
index ebf7c8f4892e2..0000000000000
--- a/spec/fixtures/api/singleton-old/package.json
+++ /dev/null
@@ -1,5 +0,0 @@
-{
-  "name": "electron-app-singleton",
-  "main": "main.js"
-}
-