diff --git a/CHANGELOG.md b/CHANGELOG.md
index 533afa2cd2c..563ae5f126c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 Expect active development and potentially significant breaking changes in the `0.x` track. We'll try to be diligent about releasing a `1.0` version in a timely fashion (ideally within 3 to 6 months), to signal the start of a more stable API.
 
 ### vNEXT
+- Fix: Update TypeScript Middleware and Afterware interfaces to include a datatype for 'this' in apply function. [PR #1372](https://github.com/apollographql/apollo-client/pull/1372)
 
 ### 1.0.0-rc.2
 - throw error if deprecated options are being used [PR #1396](https://github.com/apollographql/apollo-client/pull/1396)
@@ -520,4 +521,4 @@ This release has a minor version bump, which means npm will not automatically up
 
 ### v0.1.0
 
-Initial release. We didn't track changes before this version.
+Initial release. We didn't track changes before this version.
\ No newline at end of file
diff --git a/src/transport/afterware.ts b/src/transport/afterware.ts
index f7480c4b8cf..9f327e1975b 100644
--- a/src/transport/afterware.ts
+++ b/src/transport/afterware.ts
@@ -1,10 +1,13 @@
+import { HTTPFetchNetworkInterface } from './networkInterface';
+import { HTTPBatchedNetworkInterface } from './batchedNetworkInterface';
+
 export interface AfterwareResponse {
   response: Response;
   options: RequestInit;
 }
 
 export interface AfterwareInterface {
-  applyAfterware(response: AfterwareResponse, next: Function): any;
+  applyAfterware(this: HTTPFetchNetworkInterface, response: AfterwareResponse, next: Function): any;
 }
 
 export interface BatchAfterwareResponse {
@@ -13,5 +16,5 @@ export interface BatchAfterwareResponse {
 }
 
 export interface BatchAfterwareInterface {
-  applyBatchAfterware(response: BatchAfterwareResponse, next: Function): any;
+  applyBatchAfterware(this: HTTPBatchedNetworkInterface, response: BatchAfterwareResponse, next: Function): any;
 }
diff --git a/src/transport/middleware.ts b/src/transport/middleware.ts
index 2d80590f5da..27dfcb845bc 100644
--- a/src/transport/middleware.ts
+++ b/src/transport/middleware.ts
@@ -1,4 +1,6 @@
-import { Request } from './networkInterface';
+import { Request, HTTPFetchNetworkInterface } from './networkInterface';
+import { HTTPBatchedNetworkInterface } from './batchedNetworkInterface';
+
 
 export interface MiddlewareRequest {
   request: Request;
@@ -6,7 +8,7 @@ export interface MiddlewareRequest {
 }
 
 export interface MiddlewareInterface {
-  applyMiddleware(request: MiddlewareRequest, next: Function): void;
+  applyMiddleware(this: HTTPFetchNetworkInterface, request: MiddlewareRequest, next: Function): void;
 }
 
 export interface BatchMiddlewareRequest {
@@ -15,5 +17,5 @@ export interface BatchMiddlewareRequest {
 }
 
 export interface BatchMiddlewareInterface {
-  applyBatchMiddleware(request: BatchMiddlewareRequest, next: Function): void;
+  applyBatchMiddleware(this: HTTPBatchedNetworkInterface, request: BatchMiddlewareRequest, next: Function): void;
 }