diff --git a/package.json b/package.json
index 44cc2e88..5c7574ee 100644
--- a/package.json
+++ b/package.json
@@ -8,6 +8,7 @@
   "license": "MIT",
   "devDependencies": {
     "@types/chai": "^3.4.34",
+    "@types/glob": "^5.0.35",
     "@types/jsdom": "^11.0.1",
     "@types/mocha": "^2.2.33",
     "@types/node": "6.0.108",
diff --git a/src/CompositionHelper.test.ts b/src/CompositionHelper.test.ts
index 02231723..053a0c29 100644
--- a/src/CompositionHelper.test.ts
+++ b/src/CompositionHelper.test.ts
@@ -5,13 +5,14 @@
 
 import { assert } from 'chai';
 import { CompositionHelper } from './CompositionHelper';
+import { ITerminal } from './Types';
 
 describe('CompositionHelper', () => {
-  let terminal;
-  let compositionHelper;
-  let compositionView;
-  let textarea;
-  let handledText;
+  let terminal: ITerminal;
+  let compositionHelper: CompositionHelper;
+  let compositionView: HTMLElement;
+  let textarea: HTMLTextAreaElement;
+  let handledText: string;
 
   beforeEach(() => {
     compositionView = {
@@ -27,14 +28,14 @@ describe('CompositionHelper', () => {
         top: 0
       },
       textContent: ''
-    };
+    } as any;
     textarea = {
       value: '',
       style: {
         left: 0,
         top: 0
       }
-    };
+    } as any;
     terminal = {
       element: {
         querySelector: () => {
@@ -54,7 +55,7 @@ describe('CompositionHelper', () => {
       options: {
         lineHeight: 1
       }
-    };
+    } as any;
     handledText = '';
     compositionHelper = new CompositionHelper(textarea, compositionView, terminal);
   });
@@ -63,7 +64,7 @@ describe('CompositionHelper', () => {
     it('Should insert simple characters', (done) => {
       // First character 'ㅇ'
       compositionHelper.compositionstart();
-      compositionHelper.compositionupdate({ data: 'ㅇ' });
+      compositionHelper.compositionupdate(<CompositionEvent><CompositionEvent>{ data: 'ㅇ' });
       textarea.value = 'ㅇ';
       setTimeout(() => { // wait for any textarea updates
         compositionHelper.compositionend();
@@ -71,7 +72,7 @@ describe('CompositionHelper', () => {
           assert.equal(handledText, 'ㅇ');
           // Second character 'ㅇ'
           compositionHelper.compositionstart();
-          compositionHelper.compositionupdate({ data: 'ㅇ' });
+          compositionHelper.compositionupdate(<CompositionEvent><CompositionEvent>{ data: 'ㅇ' });
           textarea.value = 'ㅇㅇ';
           setTimeout(() => { // wait for any textarea updates
             compositionHelper.compositionend();
@@ -87,13 +88,13 @@ describe('CompositionHelper', () => {
     it('Should insert complex characters', (done) => {
       // First character '앙'
       compositionHelper.compositionstart();
-      compositionHelper.compositionupdate({ data: 'ㅇ' });
+      compositionHelper.compositionupdate(<CompositionEvent>{ data: 'ㅇ' });
       textarea.value = 'ㅇ';
       setTimeout(() => { // wait for any textarea updates
-        compositionHelper.compositionupdate({ data: '아' });
+        compositionHelper.compositionupdate(<CompositionEvent>{ data: '아' });
         textarea.value = '아';
         setTimeout(() => { // wait for any textarea updates
-          compositionHelper.compositionupdate({ data: '앙' });
+          compositionHelper.compositionupdate(<CompositionEvent>{ data: '앙' });
           textarea.value = '앙';
           setTimeout(() => { // wait for any textarea updates
             compositionHelper.compositionend();
@@ -101,13 +102,13 @@ describe('CompositionHelper', () => {
               assert.equal(handledText, '앙');
               // Second character '앙'
               compositionHelper.compositionstart();
-              compositionHelper.compositionupdate({ data: 'ㅇ' });
+              compositionHelper.compositionupdate(<CompositionEvent>{ data: 'ㅇ' });
               textarea.value = '앙ㅇ';
               setTimeout(() => { // wait for any textarea updates
-                compositionHelper.compositionupdate({ data: '아' });
+                compositionHelper.compositionupdate(<CompositionEvent>{ data: '아' });
                 textarea.value = '앙아';
                 setTimeout(() => { // wait for any textarea updates
-                  compositionHelper.compositionupdate({ data: '앙' });
+                  compositionHelper.compositionupdate(<CompositionEvent>{ data: '앙' });
                   textarea.value = '앙앙';
                   setTimeout(() => { // wait for any textarea updates
                     compositionHelper.compositionend();
@@ -127,19 +128,19 @@ describe('CompositionHelper', () => {
     it('Should insert complex characters that change with following character', (done) => {
       // First character '아'
       compositionHelper.compositionstart();
-      compositionHelper.compositionupdate({ data: 'ㅇ' });
+      compositionHelper.compositionupdate(<CompositionEvent>{ data: 'ㅇ' });
       textarea.value = 'ㅇ';
       setTimeout(() => { // wait for any textarea updates
-        compositionHelper.compositionupdate({ data: '아' });
+        compositionHelper.compositionupdate(<CompositionEvent>{ data: '아' });
         textarea.value = '아';
         setTimeout(() => { // wait for any textarea updates
           // Start second character '아' in first character
-          compositionHelper.compositionupdate({ data: '앙' });
+          compositionHelper.compositionupdate(<CompositionEvent>{ data: '앙' });
           textarea.value = '앙';
           setTimeout(() => { // wait for any textarea updates
             compositionHelper.compositionend();
             compositionHelper.compositionstart();
-            compositionHelper.compositionupdate({ data: '아' });
+            compositionHelper.compositionupdate(<CompositionEvent>{ data: '아' });
             textarea.value = '아아';
             setTimeout(() => { // wait for any textarea updates
               compositionHelper.compositionend();
@@ -156,14 +157,14 @@ describe('CompositionHelper', () => {
     it('Should insert multi-characters compositions', (done) => {
       // First character 'だ'
       compositionHelper.compositionstart();
-      compositionHelper.compositionupdate({ data: 'd' });
+      compositionHelper.compositionupdate(<CompositionEvent>{ data: 'd' });
       textarea.value = 'd';
       setTimeout(() => { // wait for any textarea updates
-        compositionHelper.compositionupdate({ data: 'だ' });
+        compositionHelper.compositionupdate(<CompositionEvent>{ data: 'だ' });
         textarea.value = 'だ';
         setTimeout(() => { // wait for any textarea updates
           // Second character 'あ'
-          compositionHelper.compositionupdate({ data: 'だあ' });
+          compositionHelper.compositionupdate(<CompositionEvent>{ data: 'だあ' });
           textarea.value = 'だあ';
           setTimeout(() => { // wait for any textarea updates
             compositionHelper.compositionend();
@@ -179,18 +180,18 @@ describe('CompositionHelper', () => {
     it('Should insert multi-character compositions that are converted to other characters with the same length', (done) => {
       // First character 'だ'
       compositionHelper.compositionstart();
-      compositionHelper.compositionupdate({ data: 'd' });
+      compositionHelper.compositionupdate(<CompositionEvent>{ data: 'd' });
       textarea.value = 'd';
       setTimeout(() => { // wait for any textarea updates
-        compositionHelper.compositionupdate({ data: 'だ' });
+        compositionHelper.compositionupdate(<CompositionEvent>{ data: 'だ' });
         textarea.value = 'だ';
         setTimeout(() => { // wait for any textarea updates
           // Second character 'ー'
-          compositionHelper.compositionupdate({ data: 'だー' });
+          compositionHelper.compositionupdate(<CompositionEvent>{ data: 'だー' });
           textarea.value = 'だー';
           setTimeout(() => { // wait for any textarea updates
             // Convert to katakana 'ダー'
-            compositionHelper.compositionupdate({ data: 'ダー' });
+            compositionHelper.compositionupdate(<CompositionEvent>{ data: 'ダー' });
             textarea.value = 'ダー';
             setTimeout(() => { // wait for any textarea updates
               compositionHelper.compositionend();
@@ -207,18 +208,18 @@ describe('CompositionHelper', () => {
     it('Should insert multi-character compositions that are converted to other characters with different lengths', (done) => {
       // First character 'い'
       compositionHelper.compositionstart();
-      compositionHelper.compositionupdate({ data: 'い' });
+      compositionHelper.compositionupdate(<CompositionEvent>{ data: 'い' });
       textarea.value = 'い';
       setTimeout(() => { // wait for any textarea updates
         // Second character 'ま'
-        compositionHelper.compositionupdate({ data: 'いm' });
+        compositionHelper.compositionupdate(<CompositionEvent>{ data: 'いm' });
         textarea.value = 'いm';
         setTimeout(() => { // wait for any textarea updates
-          compositionHelper.compositionupdate({ data: 'いま' });
+          compositionHelper.compositionupdate(<CompositionEvent>{ data: 'いま' });
           textarea.value = 'いま';
           setTimeout(() => { // wait for any textarea updates
             // Convert to kanji '今'
-            compositionHelper.compositionupdate({ data: '今' });
+            compositionHelper.compositionupdate(<CompositionEvent>{ data: '今' });
             textarea.value = '今';
             setTimeout(() => { // wait for any textarea updates
               compositionHelper.compositionend();
@@ -235,7 +236,7 @@ describe('CompositionHelper', () => {
     it('Should insert non-composition characters input immediately after composition characters', (done) => {
       // First character 'ㅇ'
       compositionHelper.compositionstart();
-      compositionHelper.compositionupdate({ data: 'ㅇ' });
+      compositionHelper.compositionupdate(<CompositionEvent>{ data: 'ㅇ' });
       textarea.value = 'ㅇ';
       setTimeout(() => { // wait for any textarea updates
         compositionHelper.compositionend();
diff --git a/src/EscapeSequenceParser.test.ts b/src/EscapeSequenceParser.test.ts
index d9ea64ce..dffbccbc 100644
--- a/src/EscapeSequenceParser.test.ts
+++ b/src/EscapeSequenceParser.test.ts
@@ -237,7 +237,7 @@ describe('EscapeSequenceParser', function (): void {
           '\x89', '\x8a', '\x8b', '\x8c', '\x8d', '\x8e', '\x8f',
           '\x91', '\x92', '\x93', '\x94', '\x95', '\x96', '\x97', '\x99', '\x9a'
         ];
-        const exceptions = {
+        const exceptions: { [key: number]: { [key: string]: any[] } } = {
           8: { '\x18': [], '\x1a': [] } // simply abort osc state
         };
         parser.reset();
@@ -247,7 +247,7 @@ describe('EscapeSequenceParser', function (): void {
             parser.currentState = state;
             parser.parse(exes[i]);
             chai.expect(parser.currentState).equal(ParserState.GROUND);
-            testTerminal.compare(((exceptions[state]) ? exceptions[state][exes[i]] : 0) || [['exe', exes[i]]]);
+            testTerminal.compare((state in exceptions ? exceptions[state][exes[i]] : 0) || [['exe', exes[i]]]);
             parser.reset();
             testTerminal.clear();
           }
@@ -1099,20 +1099,20 @@ describe('EscapeSequenceParser', function (): void {
 
   describe('set/clear handler', function (): void {
     const INPUT = '\x1b[1;31mhello \x1b%Gwor\x1bEld!\x1b[0m\r\n$>\x1b]1;foo=bar\x1b\\';
-    let parser2 = null;
+    let parser2: TestEscapeSequenceParser = null;
     let print = '';
-    let esc = [];
-    let csi = [];
-    let exe = [];
-    let osc = [];
-    let dcs = [];
+    const esc: string[] = [];
+    const csi: [string, number[], string][] = [];
+    const exe: string[] = [];
+    const osc: [number, string][] = [];
+    const dcs: ([string] | [string, string] | [string, string, number[], number])[] = [];
     function clearAccu(): void {
       print = '';
-      esc = [];
-      csi = [];
-      exe = [];
-      osc = [];
-      dcs = [];
+      esc.length = 0;
+      csi.length = 0;
+      exe.length = 0;
+      osc.length = 0;
+      dcs.length = 0;
     }
     beforeEach(function (): void {
       parser2 = new TestEscapeSequenceParser();
diff --git a/src/InputHandler.ts b/src/InputHandler.ts
index f5db133f..16fedea2 100644
--- a/src/InputHandler.ts
+++ b/src/InputHandler.ts
@@ -15,7 +15,7 @@ import { EscapeSequenceParser } from './EscapeSequenceParser';
 /**
  * Map collect to glevel. Used in `selectCharset`.
  */
-const GLEVEL = {'(': 0, ')': 1, '*': 2, '+': 3, '-': 1, '.': 2};
+const GLEVEL: {[key: string]: number} = {'(': 0, ')': 1, '*': 2, '+': 3, '-': 1, '.': 2};
 
 
 /**
@@ -77,7 +77,7 @@ class DECRQSS implements IDcsHandler {
         // TODO: report real settings instead of 0m
         return this._terminal.send(`${C0.ESC}P1$r0m${C0.ESC}\\`);
       case ' q': // DECSCUSR
-        const STYLES = {'block': 2, 'underline': 4, 'bar': 6};
+        const STYLES: {[key: string]: number} = {'block': 2, 'underline': 4, 'bar': 6};
         let style = STYLES[this._terminal.getOption('cursorStyle')];
         style -= this._terminal.getOption('cursorBlink');
         return this._terminal.send(`${C0.ESC}P1$r${style} q${C0.ESC}\\`);
diff --git a/src/Terminal.integration.ts b/src/Terminal.integration.ts
index 54e76518..bb50d2d0 100644
--- a/src/Terminal.integration.ts
+++ b/src/Terminal.integration.ts
@@ -14,6 +14,11 @@ import * as pty from 'node-pty';
 import { assert } from 'chai';
 import { Terminal } from './Terminal';
 import { CHAR_DATA_CHAR_INDEX } from './Buffer';
+import { IViewport } from './Types';
+
+class TestTerminal extends Terminal {
+  innerWrite(): void { this._innerWrite(); }
+}
 
 let primitivePty: any;
 
@@ -87,12 +92,12 @@ if (os.platform() !== 'win32') {
 
   /** tests */
   describe('xterm output comparison', () => {
-    let xterm;
+    let xterm: TestTerminal;
 
     beforeEach(() => {
-      xterm = new Terminal({ cols: COLS, rows: ROWS });
+      xterm = new TestTerminal({ cols: COLS, rows: ROWS });
       xterm.refresh = () => {};
-      xterm.viewport = {
+      xterm.viewport = <IViewport>{
         syncScrollArea: () => {}
       };
     });
@@ -125,7 +130,7 @@ if (os.platform() !== 'win32') {
 
               // Perform a synchronous .write(data)
               xterm.writeBuffer.push(fromPty);
-              xterm._innerWrite();
+              xterm.innerWrite();
 
               const fromEmulator = terminalToString(xterm);
               console.log = CONSOLE_LOG;
diff --git a/src/Terminal.test.ts b/src/Terminal.test.ts
index 5b7039e9..f6cbad52 100644
--- a/src/Terminal.test.ts
+++ b/src/Terminal.test.ts
@@ -176,7 +176,7 @@ describe('term.js addons', () => {
 
   describe('scroll', () => {
     describe('scrollLines', () => {
-      let startYDisp;
+      let startYDisp: number;
       beforeEach(() => {
         for (let i = 0; i < term.rows * 2; i++) {
           term.writeln('test');
@@ -211,7 +211,7 @@ describe('term.js addons', () => {
     });
 
     describe('scrollPages', () => {
-      let startYDisp;
+      let startYDisp: number;
       beforeEach(() => {
         for (let i = 0; i < term.rows * 3; i++) {
           term.writeln('test');
@@ -248,7 +248,7 @@ describe('term.js addons', () => {
     });
 
     describe('scrollToBottom', () => {
-      let startYDisp;
+      let startYDisp: number;
       beforeEach(() => {
         for (let i = 0; i < term.rows * 3; i++) {
           term.writeln('test');
@@ -269,7 +269,7 @@ describe('term.js addons', () => {
     });
 
     describe('scrollToLine', () => {
-      let startYDisp;
+      let startYDisp: number;
       beforeEach(() => {
         for (let i = 0; i < term.rows * 3; i++) {
           term.writeln('test');
@@ -712,8 +712,8 @@ describe('term.js addons', () => {
   });
 
   describe('Third level shift', () => {
-    let evKeyDown;
-    let evKeyPress;
+    let evKeyDown: any;
+    let evKeyPress: any;
 
     beforeEach(() => {
       term.handler = () => {};
diff --git a/src/Terminal.ts b/src/Terminal.ts
index 63f7efdb..92ab39e1 100644
--- a/src/Terminal.ts
+++ b/src/Terminal.ts
@@ -51,7 +51,7 @@ import { ITheme, ILocalizableStrings, IMarker, IDisposable } from 'xterm';
 import { removeTerminalFromCache } from './renderer/atlas/CharAtlasCache';
 
 // reg + shift key mappings for digits and special chars
-const KEYCODE_KEY_MAPPINGS = {
+const KEYCODE_KEY_MAPPINGS: { [key: number]: [string, string]} = {
   // digits 0-9
   48: ['0', ')'],
   49: ['1', '!'],
@@ -277,8 +277,6 @@ export class Terminal extends EventEmitter implements ITerminal, IDisposable, II
       if (this.options[key] == null) {
         this.options[key] = DEFAULT_OPTIONS[key];
       }
-      // TODO: We should move away from duplicate options on the Terminal object
-      this[key] = this.options[key];
     });
 
     // this.context = options.context || window;
@@ -384,11 +382,7 @@ export class Terminal extends EventEmitter implements ITerminal, IDisposable, II
       throw new Error('No option with key "' + key + '"');
     }
 
-    if (typeof this.options[key] !== 'undefined') {
-      return this.options[key];
-    }
-
-    return this[key];
+    return this.options[key];
   }
 
   /**
@@ -462,7 +456,6 @@ export class Terminal extends EventEmitter implements ITerminal, IDisposable, II
         }
         break;
     }
-    this[key] = value;
     this.options[key] = value;
     switch (key) {
       case 'fontFamily':
@@ -561,7 +554,7 @@ export class Terminal extends EventEmitter implements ITerminal, IDisposable, II
       }
       copyHandler(event, this, this.selectionManager);
     });
-    const pasteHandlerWrapper = event => pasteHandler(event, this);
+    const pasteHandlerWrapper = (event: ClipboardEvent) => pasteHandler(event, this);
     on(this.textarea, 'paste', pasteHandlerWrapper);
     on(this.element, 'paste', pasteHandlerWrapper);
 
@@ -1292,7 +1285,7 @@ export class Terminal extends EventEmitter implements ITerminal, IDisposable, II
     }
   }
 
-  private _innerWrite(): void {
+  protected _innerWrite(): void {
     const writeBatch = this.writeBuffer.splice(0, WRITE_BATCH_SIZE);
     while (writeBatch.length > 0) {
       const data = writeBatch.shift();
diff --git a/src/Types.ts b/src/Types.ts
index 5075daa9..97a6f9e4 100644
--- a/src/Types.ts
+++ b/src/Types.ts
@@ -261,6 +261,7 @@ export interface ICharMeasure {
 
 // TODO: The options that are not in the public API should be reviewed
 export interface ITerminalOptions extends IPublicTerminalOptions {
+  [key: string]: any;
   cancelEvents?: boolean;
   convertEol?: boolean;
   debug?: boolean;
diff --git a/src/addons/attach/attach.ts b/src/addons/attach/attach.ts
index d0e8bd4b..e6d92b56 100644
--- a/src/addons/attach/attach.ts
+++ b/src/addons/attach/attach.ts
@@ -36,10 +36,11 @@ export function attach(term: Terminal, socket: WebSocket, bidirectional: boolean
     }
   };
 
-  let myTextDecoder;
+  // TODO: This should be typed but there seem to be issues importing the type
+  let myTextDecoder: any;
 
   addonTerminal.__getMessage = function(ev: MessageEvent): void {
-    let str;
+    let str: string;
 
     if (typeof ev.data === 'object') {
       if (!myTextDecoder) {
diff --git a/src/renderer/ColorManager.test.ts b/src/renderer/ColorManager.test.ts
index 0012c1ed..26fb2895 100644
--- a/src/renderer/ColorManager.test.ts
+++ b/src/renderer/ColorManager.test.ts
@@ -36,7 +36,7 @@ describe('ColorManager', () => {
       for (const key of Object.keys(cm.colors)) {
         if (key !== 'ansi') {
           // A #rrggbb or rgba(...)
-          assert.ok(cm.colors[key].css.length >= 7);
+          assert.ok((<any>cm.colors)[key].css.length >= 7);
         }
       }
       assert.equal(cm.colors.ansi.length, 256);
diff --git a/src/renderer/atlas/CharAtlasUtils.ts b/src/renderer/atlas/CharAtlasUtils.ts
index 39284d32..59ac07df 100644
--- a/src/renderer/atlas/CharAtlasUtils.ts
+++ b/src/renderer/atlas/CharAtlasUtils.ts
@@ -9,7 +9,7 @@ import { ICharAtlasConfig } from '../../shared/atlas/Types';
 
 export function generateConfig(scaledCharWidth: number, scaledCharHeight: number, terminal: ITerminal, colors: IColorSet): ICharAtlasConfig {
   // null out some fields that don't matter
-  const clonedColors = {
+  const clonedColors = <IColorSet>{
     foreground: colors.foreground,
     background: colors.background,
     cursor: null,
diff --git a/src/renderer/atlas/LRUMap.ts b/src/renderer/atlas/LRUMap.ts
index 4a03f2aa..eccfbfea 100644
--- a/src/renderer/atlas/LRUMap.ts
+++ b/src/renderer/atlas/LRUMap.ts
@@ -11,7 +11,7 @@ interface ILinkedListNode<T> {
 }
 
 export default class LRUMap<T> {
-  private _map = {};
+  private _map: { [key: string]: ILinkedListNode<T> } = {};
   private _head: ILinkedListNode<T> = null;
   private _tail: ILinkedListNode<T> = null;
   private _nodePool: ILinkedListNode<T>[] = [];
diff --git a/src/shared/atlas/CharAtlasGenerator.ts b/src/shared/atlas/CharAtlasGenerator.ts
index e0cfbcf7..f78a6d41 100644
--- a/src/shared/atlas/CharAtlasGenerator.ts
+++ b/src/shared/atlas/CharAtlasGenerator.ts
@@ -106,7 +106,7 @@ export function generateStaticCharAtlasTexture(context: Window, canvasFactory: (
       return canvas;
     }
     // Transfer to an ImageBitmap is this is an OffscreenCanvas
-    return new Promise(r => r(canvas.transferToImageBitmap()));
+    return new Promise((r: (bitmap: ImageBitmap) => void) => r(canvas.transferToImageBitmap()));
   }
 
   const charAtlasImageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
diff --git a/src/utils/Clone.test.ts b/src/utils/Clone.test.ts
index f5708a9e..b24452c8 100644
--- a/src/utils/Clone.test.ts
+++ b/src/utils/Clone.test.ts
@@ -39,7 +39,7 @@ describe('clone', () => {
   });
 
   it('should clone null values', () => {
-    const test = {
+    const test: any = {
       a: null
     };
 
diff --git a/src/utils/TestUtils.test.ts b/src/utils/TestUtils.test.ts
index e3ae89d3..42c4d974 100644
--- a/src/utils/TestUtils.test.ts
+++ b/src/utils/TestUtils.test.ts
@@ -267,7 +267,7 @@ export class MockInputHandlingTerminal implements IInputHandlingTerminal {
     throw new Error('Method not implemented.');
   }
   setOption(key: string, value: any): void {
-    this.options[key] = value;
+    (<any>this.options)[key] = value;
   }
   on(type: string, listener: XtermListener): void {
     throw new Error('Method not implemented.');
diff --git a/tsconfig.json b/tsconfig.json
index 2e7404e2..c33793f5 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -12,7 +12,8 @@
     "outDir": "lib",
     "sourceMap": true,
     "removeComments": true,
-    "noUnusedLocals": true
+    "noUnusedLocals": true,
+    "noImplicitAny": true
   },
   "include": [
     "src/**/*",