diff --git a/.eslintrc b/.eslintrc
index df091ac4297b1..39bec1a73cdd4 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -58,6 +58,10 @@
         "microsoft-typescript/object-literal-surrounding-space": "error",
         "microsoft-typescript/no-type-assertion-whitespace": "error",
         "microsoft-typescript/type-operator-spacing": "error",
+        "microsoft-typescript/only-arrow-functions": ["error", {
+            "allowNamedFunctions": true ,
+            "allowDeclarations": true
+        }],
         "microsoft-typescript/no-double-space": "error",
         "microsoft-typescript/boolean-trivia": "error",
         "microsoft-typescript/no-in-operator": "error",
diff --git a/scripts/authors.ts b/scripts/authors.ts
index 8f771df89569b..66233d9651094 100644
--- a/scripts/authors.ts
+++ b/scripts/authors.ts
@@ -100,18 +100,18 @@ function sortAuthors(a: string, b: string) {
 }
 
 namespace Commands {
-    export const writeAuthors: Command = function () {
+    export const writeAuthors: Command = () => {
         const output = deduplicate(getKnownAuthors().map(getAuthorName).filter(a => !!a)).sort(sortAuthors).join("\r\n* ");
         fs.writeFileSync(authorsPath, "TypeScript is authored by:\r\n* " + output);
     };
     writeAuthors.description = "Write known authors to AUTHORS.md file.";
 
-    export const listKnownAuthors: Command = function () {
+    export const listKnownAuthors: Command = () => {
         deduplicate(getKnownAuthors().map(getAuthorName)).filter(a => !!a).sort(sortAuthors).forEach(log);
     };
     listKnownAuthors.description = "List known authors as listed in .mailmap file.";
 
-    export const listAuthors: Command = function (...specs: string[]) {
+    export const listAuthors: Command = (...specs: string[]) => {
         const cmd = "git shortlog -se " + specs.join(" ");
         console.log(cmd);
         const outputRegExp = /\d+\s+([^<]+)<([^>]+)>/;
@@ -137,7 +137,7 @@ namespace Commands {
 
             const maps = getKnownAuthorMaps();
 
-            const lookupAuthor = function ({name, email}: { name: string, email: string }) {
+            const lookupAuthor = ({name, email}: { name: string, email: string }) => {
                 return maps.authorsByEmail[email.toLocaleLowerCase()] || maps.authorsByName[name];
             };
 
diff --git a/scripts/importDefinitelyTypedTests/importDefinitelyTypedTests.ts b/scripts/importDefinitelyTypedTests/importDefinitelyTypedTests.ts
index f7625f411498d..ae7b1b4acb725 100644
--- a/scripts/importDefinitelyTypedTests/importDefinitelyTypedTests.ts
+++ b/scripts/importDefinitelyTypedTests/importDefinitelyTypedTests.ts
@@ -115,7 +115,7 @@ function importDefinitelyTypedTests(tscPath: string, rwcTestPath: string, defini
             .filter(i => fs.statSync(path.join(definitelyTypedRoot, i)).isDirectory())
             .forEach(d => {
                 const directoryPath = path.join(definitelyTypedRoot, d);
-                fs.readdir(directoryPath, function (err, files) {
+                fs.readdir(directoryPath, (err, files) => {
                     if (err) {
                         throw err;
                     }
diff --git a/scripts/word2md.ts b/scripts/word2md.ts
index 21ad578bab386..281ffc6215481 100644
--- a/scripts/word2md.ts
+++ b/scripts/word2md.ts
@@ -131,7 +131,7 @@ module Word { // eslint-disable-line @typescript-eslint/prefer-namespace-keyword
     }
 }
 
-const sys = (function () {
+const sys = (function () { // eslint-disable-line microsoft-typescript/only-arrow-functions
     const fileStream = new ActiveXObject("ADODB.Stream");
     fileStream.Type = 2 /*text*/;
     const binaryStream = new ActiveXObject("ADODB.Stream");
diff --git a/src/harness/harnessLanguageService.ts b/src/harness/harnessLanguageService.ts
index 692bd73c67d71..949ac5dda7aba 100644
--- a/src/harness/harnessLanguageService.ts
+++ b/src/harness/harnessLanguageService.ts
@@ -4,7 +4,7 @@ namespace Harness.LanguageService {
         const proxy = Object.create(/*prototype*/ null); // eslint-disable-line no-null/no-null
         const langSvc: any = info.languageService;
         for (const k of Object.keys(langSvc)) {
-            proxy[k] = function () {
+            proxy[k] = function () { // eslint-disable-line microsoft-typescript/only-arrow-functions
                 return langSvc[k].apply(langSvc, arguments);
             };
         }
@@ -796,7 +796,7 @@ namespace Harness.LanguageService {
                             create(info: ts.server.PluginCreateInfo) {
                                 const proxy = makeDefaultProxy(info);
                                 const langSvc: any = info.languageService;
-                                proxy.getQuickInfoAtPosition = function () {
+                                proxy.getQuickInfoAtPosition = function () { // eslint-disable-line microsoft-typescript/only-arrow-functions
                                     const parts = langSvc.getQuickInfoAtPosition.apply(langSvc, arguments);
                                     if (parts.displayParts.length > 0) {
                                         parts.displayParts[0].text = "Proxied";
diff --git a/src/harness/loggedIO.ts b/src/harness/loggedIO.ts
index 480efb6d4bbdc..57fa8097e523f 100644
--- a/src/harness/loggedIO.ts
+++ b/src/harness/loggedIO.ts
@@ -363,7 +363,7 @@ namespace Playback {
 
     function recordReplay<T extends ts.AnyFunction>(original: T, underlying: any) {
         function createWrapper(record: T, replay: T): T {
-            return <any>(function () {
+            return <any>(function () { // eslint-disable-line microsoft-typescript/only-arrow-functions
                 if (replayLog !== undefined) {
                     return replay.apply(undefined, arguments);
                 }