diff --git a/src/lib/decorators.ts b/src/lib/decorators.ts
index bc72e65e..f5a2eb36 100644
--- a/src/lib/decorators.ts
+++ b/src/lib/decorators.ts
@@ -18,7 +18,7 @@ import {LitElement} from '../lit-element.js';
 import {PropertyDeclaration, UpdatingElement} from './updating-element.js';
 
 export type Constructor<T> = {
-  new (...args: any[]): T
+  new (...args: unknown[]): T
 };
 
 // From the TC39 Decorators proposal
@@ -47,6 +47,7 @@ const legacyCustomElement =
       // `Constructor<HTMLElement>` for some reason.
       // `Constructor<HTMLElement>` is helpful to make sure the decorator is
       // applied to elements however.
+      // tslint:disable-next-line:no-any
       return clazz as any;
     };
 
@@ -106,6 +107,7 @@ const standardProperty =
           //     initializer: descriptor.initializer,
           //   }
           // ],
+          // tslint:disable-next-line:no-any decorator
           initializer(this: any) {
             if (typeof element.initializer === 'function') {
               this[element.key] = element.initializer!.call(this);
@@ -132,6 +134,7 @@ const legacyProperty =
  * @ExportDecoratedItems
  */
 export function property(options?: PropertyDeclaration) {
+  // tslint:disable-next-line:no-any decorator
   return (protoOrDescriptor: Object|ClassElement, name?: PropertyKey): any =>
              (name !== undefined) ?
       legacyProperty(options!, protoOrDescriptor as Object, name) :
@@ -177,6 +180,7 @@ const standardQuery = (descriptor: PropertyDescriptor, element: ClassElement) =>
 function _query<T>(queryFn: (target: NodeSelector, selector: string) => T) {
   return (selector: string) =>
              (protoOrDescriptor: Object|ClassElement,
+              // tslint:disable-next-line:no-any decorator
               name?: PropertyKey): any => {
                const descriptor = {
                  get(this: LitElement) {
@@ -203,6 +207,7 @@ const standardEventOptions =
     };
 
 const legacyEventOptions =
+    // tslint:disable-next-line:no-any legacy decorator
     (options: AddEventListenerOptions, proto: any, name: PropertyKey) => {
       Object.assign(proto[name], options);
     };
@@ -243,4 +248,5 @@ export const eventOptions = (options: AddEventListenerOptions) =>
          (name !== undefined) ?
          legacyEventOptions(options, protoOrDescriptor as Object, name) :
          standardEventOptions(options, protoOrDescriptor as ClassElement)) as
-    any;
+        // tslint:disable-next-line:no-any decorator
+        any;
diff --git a/src/lib/updating-element.ts b/src/lib/updating-element.ts
index f753dc08..cd8ac8bc 100644
--- a/src/lib/updating-element.ts
+++ b/src/lib/updating-element.ts
@@ -33,27 +33,30 @@ declare global {
 /**
  * Converts property values to and from attribute values.
  */
-export interface ComplexAttributeConverter<Type = any, TypeHint = any> {
+export interface ComplexAttributeConverter<Type = unknown, TypeHint = unknown> {
   /**
    * Function called to convert an attribute value to a property
    * value.
    */
-  fromAttribute?(value: string, type?: TypeHint): Type;
+  fromAttribute?(value: string|null, type?: TypeHint): Type;
 
   /**
    * Function called to convert a property value to an attribute
    * value.
+   *
+   * It returns unknown instead of string, to be compatible with
+   * https://github.com/WICG/trusted-types (and similar efforts).
    */
-  toAttribute?(value: Type, type?: TypeHint): string|null;
+  toAttribute?(value: Type, type?: TypeHint): unknown;
 }
 
-type AttributeConverter<Type = any, TypeHint = any> =
+type AttributeConverter<Type = unknown, TypeHint = unknown> =
     ComplexAttributeConverter<Type>|((value: string, type?: TypeHint) => Type);
 
 /**
  * Defines options for a property accessor.
  */
-export interface PropertyDeclaration<Type = any, TypeHint = any> {
+export interface PropertyDeclaration<Type = unknown, TypeHint = unknown> {
   /**
    * Indicates how and whether the property becomes an observed attribute.
    * If the value is `false`, the property is not added to `observedAttributes`.
@@ -61,14 +64,14 @@ export interface PropertyDeclaration<Type = any, TypeHint = any> {
    * becomes `foobar`). If a string, the string value is observed (e.g
    * `attribute: 'foo-bar'`).
    */
-  attribute?: boolean|string;
+  readonly attribute?: boolean|string;
 
   /**
    * Indicates the type of the property. This is used only as a hint for the
    * `converter` to determine how to convert the attribute
    * to/from a property.
    */
-  type?: TypeHint;
+  readonly type?: TypeHint;
 
   /**
    * Indicates how to convert the attribute to/from a property. If this value
@@ -82,7 +85,7 @@ export interface PropertyDeclaration<Type = any, TypeHint = any> {
    * the property is never updated again as a result of the attribute changing,
    * and vice versa.
    */
-  converter?: AttributeConverter<Type, TypeHint>;
+  readonly converter?: AttributeConverter<Type, TypeHint>;
 
   /**
    * Indicates if the property should reflect to an attribute.
@@ -91,7 +94,7 @@ export interface PropertyDeclaration<Type = any, TypeHint = any> {
    * property option and the value of the property converted using the rules
    * from the `converter` property option.
    */
-  reflect?: boolean;
+  readonly reflect?: boolean;
 
   /**
    * A function that indicates if a property should be considered changed when
@@ -108,7 +111,7 @@ export interface PropertyDeclaration<Type = any, TypeHint = any> {
    * `this.requestUpdate(propertyName, oldValue)` to request an update when
    * the property changes.
    */
-  noAccessor?: boolean;
+  readonly noAccessor?: boolean;
 }
 
 /**
@@ -117,7 +120,7 @@ export interface PropertyDeclaration<Type = any, TypeHint = any> {
  * PropertyDeclaration options.
  */
 export interface PropertyDeclarations {
-  [key: string]: PropertyDeclaration;
+  readonly [key: string]: PropertyDeclaration;
 }
 
 type PropertyDeclarationMap = Map<PropertyKey, PropertyDeclaration>;
@@ -128,7 +131,7 @@ export type PropertyValues = Map<PropertyKey, unknown>;
 
 export const defaultConverter: ComplexAttributeConverter = {
 
-  toAttribute(value: any, type?: any) {
+  toAttribute(value: unknown, type?: unknown): unknown {
     switch (type) {
       case Boolean:
         return value ? '' : null;
@@ -141,7 +144,7 @@ export const defaultConverter: ComplexAttributeConverter = {
     return value;
   },
 
-  fromAttribute(value: any, type?: any) {
+  fromAttribute(value: string|null, type?: unknown) {
     switch (type) {
       case Boolean:
         return value !== null;
@@ -149,7 +152,7 @@ export const defaultConverter: ComplexAttributeConverter = {
         return value === null ? null : Number(value);
       case Object:
       case Array:
-        return JSON.parse(value);
+        return JSON.parse(value!);
     }
     return value;
   }
@@ -256,10 +259,12 @@ export abstract class UpdatingElement extends HTMLElement {
             JSCompiler_renameProperty('_classProperties', this))) {
       this._classProperties = new Map();
       // NOTE: Workaround IE11 not supporting Map constructor argument.
-      const superProperties = Object.getPrototypeOf(this)._classProperties;
+      const superProperties: PropertyDeclarationMap =
+          Object.getPrototypeOf(this)._classProperties;
       if (superProperties !== undefined) {
         superProperties.forEach(
-            (v: any, k: PropertyKey) => this._classProperties!.set(k, v));
+            (v: PropertyDeclaration, k: PropertyKey) =>
+                this._classProperties!.set(k, v));
       }
     }
   }
@@ -289,11 +294,15 @@ export abstract class UpdatingElement extends HTMLElement {
     }
     const key = typeof name === 'symbol' ? Symbol() : `__${name}`;
     Object.defineProperty(this.prototype, name, {
+      // tslint:disable-next-line:no-any no symbol in index
       get(): any {
+        // tslint:disable-next-line:no-any no symbol in index
         return (this as any)[key];
       },
-      set(this: UpdatingElement, value: any) {
+      set(this: UpdatingElement, value: unknown) {
+        // tslint:disable-next-line:no-any no symbol in index
         const oldValue = (this as any)[name];
+        // tslint:disable-next-line:no-any no symbol in index
         (this as any)[key] = value;
         this.requestUpdate(name, oldValue);
       },
@@ -338,6 +347,7 @@ export abstract class UpdatingElement extends HTMLElement {
       for (const p of propKeys) {
         // note, use of `any` is due to TypeSript lack of support for symbol in
         // index types
+        // tslint:disable-next-line:no-any no symbol in index
         this.createProperty(p, (props as any)[p]);
       }
     }
@@ -375,7 +385,7 @@ export abstract class UpdatingElement extends HTMLElement {
    * @nocollapse
    */
   private static _propertyValueFromAttribute(
-      value: string, options: PropertyDeclaration) {
+      value: string|null, options: PropertyDeclaration) {
     const type = options.type;
     const converter = options.converter || defaultConverter;
     const fromAttribute =
@@ -468,6 +478,7 @@ export abstract class UpdatingElement extends HTMLElement {
   private _applyInstanceProperties() {
     // Use forEach so this works even if for/of loops are compiled to for loops
     // expecting arrays
+    // tslint:disable-next-line:no-any
     this._instanceProperties!.forEach((v, p) => (this as any)[p] = v);
     this._instanceProperties = undefined;
   }
@@ -497,7 +508,7 @@ export abstract class UpdatingElement extends HTMLElement {
   /**
    * Synchronizes property values when attributes change.
    */
-  attributeChangedCallback(name: string, old: string, value: string) {
+  attributeChangedCallback(name: string, old: string|null, value: string|null) {
     if (old !== value) {
       this._attributeToProperty(name, value);
     }
@@ -526,14 +537,14 @@ export abstract class UpdatingElement extends HTMLElement {
       if (attrValue == null) {
         this.removeAttribute(attr);
       } else {
-        this.setAttribute(attr, attrValue);
+        this.setAttribute(attr, attrValue as string);
       }
       // mark state not reflecting
       this._updateState = this._updateState & ~STATE_IS_REFLECTING_TO_ATTRIBUTE;
     }
   }
 
-  private _attributeToProperty(name: string, value: string) {
+  private _attributeToProperty(name: string, value: string|null) {
     // Use tracking info to avoid deserializing attribute value if it was
     // just set from a property setter.
     if (this._updateState & STATE_IS_REFLECTING_TO_ATTRIBUTE) {
@@ -547,7 +558,8 @@ export abstract class UpdatingElement extends HTMLElement {
       // mark state reflecting
       this._updateState = this._updateState | STATE_IS_REFLECTING_TO_PROPERTY;
       this[propName as keyof this] =
-          ctor._propertyValueFromAttribute(value, options);
+          // tslint:disable-next-line:no-any
+          ctor._propertyValueFromAttribute(value, options) as any;
       // mark state not reflecting
       this._updateState = this._updateState & ~STATE_IS_REFLECTING_TO_PROPERTY;
     }
@@ -566,7 +578,7 @@ export abstract class UpdatingElement extends HTMLElement {
    * @param oldValue {any} (optional) old value of requesting property
    * @returns {Promise} A Promise that is resolved when the update completes.
    */
-  requestUpdate(name?: PropertyKey, oldValue?: any) {
+  requestUpdate(name?: PropertyKey, oldValue?: unknown) {
     let shouldRequestUpdate = true;
     // if we have a property key, perform property update steps.
     if (name !== undefined && !this._changedProperties.has(name)) {
diff --git a/src/lit-element.ts b/src/lit-element.ts
index 558ec603..e2bbada9 100644
--- a/src/lit-element.ts
+++ b/src/lit-element.ts
@@ -208,7 +208,7 @@ export class LitElement extends UpdatingElement {
    */
   protected update(changedProperties: PropertyValues) {
     super.update(changedProperties);
-    const templateResult = this.render() as any;
+    const templateResult = this.render() as unknown;
     if (templateResult instanceof TemplateResult) {
       (this.constructor as typeof LitElement)
           .render(
diff --git a/src/test/lib/decorators_test.ts b/src/test/lib/decorators_test.ts
index c63b7a2f..9ecbfcff 100644
--- a/src/test/lib/decorators_test.ts
+++ b/src/test/lib/decorators_test.ts
@@ -16,6 +16,8 @@ import {eventOptions, property} from '../../lib/decorators.js';
 import {customElement, html, LitElement, PropertyValues, query, queryAll} from '../../lit-element.js';
 import {generateElementName} from '../test-helpers.js';
 
+// tslint:disable:no-any ok in tests
+
 let hasOptions;
 const supportsOptions = (function() {
   if (hasOptions !== undefined) {
diff --git a/src/test/lib/updating-element_test.ts b/src/test/lib/updating-element_test.ts
index ebcea360..8daa277f 100644
--- a/src/test/lib/updating-element_test.ts
+++ b/src/test/lib/updating-element_test.ts
@@ -16,6 +16,8 @@ import {property} from '../../lib/decorators.js';
 import {ComplexAttributeConverter, PropertyDeclarations, PropertyValues, UpdatingElement} from '../../lib/updating-element.js';
 import {generateElementName} from '../test-helpers.js';
 
+// tslint:disable:no-any ok in tests
+
 const assert = chai.assert;
 
 suite('UpdatingElement', () => {
diff --git a/src/test/lit-element_styling_test.ts b/src/test/lit-element_styling_test.ts
index 1a34a58d..819db6e4 100644
--- a/src/test/lit-element_styling_test.ts
+++ b/src/test/lit-element_styling_test.ts
@@ -456,6 +456,7 @@ suite('Static get styles', () => {
 
   test('`css` get styles throws when unsafe values are used', async () => {
     assert.throws(() => {
+      // tslint:disable:no-any intentionally unsafe code
       css`div { border: ${`2px solid blue;` as any}}`;
     });
   });
diff --git a/src/test/lit-element_test.ts b/src/test/lit-element_test.ts
index 89b9dc2e..72c18b5c 100644
--- a/src/test/lit-element_test.ts
+++ b/src/test/lit-element_test.ts
@@ -18,6 +18,8 @@ import {generateElementName, stripExpressionDelimeters} from './test-helpers.js'
 
 const assert = chai.assert;
 
+// tslint:disable:no-any ok in tests
+
 suite('LitElement', () => {
   let container: HTMLElement;
 
diff --git a/tsconfig.json b/tsconfig.json
index 1aa2cc75..b904df43 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -13,6 +13,8 @@
     "noUnusedParameters": true,
     "noImplicitReturns": true,
     "noFallthroughCasesInSwitch": true,
+    "noImplicitAny": true,
+    "noImplicitThis": true,
     "outDir": "./",
     // Only necessary because @types/uglify-js can't find types for source-map
     "skipLibCheck": true,
diff --git a/tslint.json b/tslint.json
index 54984fb6..7b4fc2a9 100644
--- a/tslint.json
+++ b/tslint.json
@@ -7,6 +7,7 @@
       "spaces"
     ],
     "prefer-const": true,
+    "no-any": true,
     "no-duplicate-variable": true,
     "no-eval": true,
     "no-internal-module": true,