diff --git a/types/chai/index.d.ts b/types/chai/index.d.ts
index f649bee49e..d7fb0492a8 100644
--- a/types/chai/index.d.ts
+++ b/types/chai/index.d.ts
@@ -11,7 +11,8 @@
 //                 Satana Charuwichitratana <https://github.com/micksatana>,
 //                 Erik Schierboom <https://github.com/ErikSchierboom>,
 //                 Bogdan Paranytsia <https://github.com/bparan>,
-//                 CXuesong <https://github.com/CXuesong>
+//                 CXuesong <https://github.com/CXuesong>,
+//                 Joey Kilpatrick <https://github.com/joeykilpatrick>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 // TypeScript Version: 3.0
 
@@ -103,7 +104,8 @@ declare namespace Chai {
 
     export interface ExpectStatic {
         (val: any, message?: string): Assertion;
-        fail(actual?: any, expected?: any, message?: string, operator?: Operator): void;
+        fail(message?: string): never;
+        fail(actual: any, expected: any, message?: string, operator?: Operator): never;
     }
 
     export interface AssertStatic extends Assert {
@@ -167,7 +169,8 @@ declare namespace Chai {
 
     interface Should extends ShouldAssertion {
         not: ShouldAssertion;
-        fail(actual: any, expected: any, message?: string, operator?: Operator): void;
+        fail(message?: string): never;
+        fail(actual: any, expected: any, message?: string, operator?: Operator): never;
     }
 
     interface ShouldThrow {
@@ -396,6 +399,14 @@ declare namespace Chai {
          */
         (expression: any, message?: string): void;
 
+        /**
+         * Throws a failure.
+         *
+         * @param message    Message to display on error.
+         * @remarks Node.js assert module-compatible.
+         */
+        fail(message?: string): never;
+
         /**
          * Throws a failure.
          *
@@ -406,7 +417,7 @@ declare namespace Chai {
          * @param operator   Comparison operator, if not strict equality.
          * @remarks Node.js assert module-compatible.
          */
-        fail<T>(actual?: T, expected?: T, message?: string, operator?: Operator): void;
+        fail<T>(actual: T, expected: T, message?: string, operator?: Operator): never;
 
         /**
          * Asserts that object is truthy.