diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index afd2ddad9e157..f099d8581191a 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -720,8 +720,9 @@ namespace ts {
             const typesFile = tryReadTypesSection(packageJsonPath, candidate, state);
             if (typesFile) {
                 const onlyRecordFailures = !directoryProbablyExists(getDirectoryPath(typesFile), state.host);
-                // The package.json "typings" property must specify the file with extension, so just try that exact filename.
-                const result = tryFile(typesFile, failedLookupLocation, onlyRecordFailures, state);
+                // A package.json "typings" may specify an exact filename, or may choose to omit an extension.
+                const result = tryFile(typesFile, failedLookupLocation, onlyRecordFailures, state) ||
+                    tryAddingExtensions(typesFile, extensions, failedLookupLocation, onlyRecordFailures, state);
                 if (result) {
                     return result;
                 }
diff --git a/tests/baselines/reference/typingsLookup4.js b/tests/baselines/reference/typingsLookup4.js
new file mode 100644
index 0000000000000..c11bc13c6138b
--- /dev/null
+++ b/tests/baselines/reference/typingsLookup4.js
@@ -0,0 +1,36 @@
+//// [tests/cases/conformance/typings/typingsLookup4.ts] ////
+
+//// [package.json]
+{ "typings": "jquery.d.ts" }
+
+//// [jquery.d.ts]
+export const j: number;
+
+//// [package.json]
+{ "typings": "kquery" }
+
+//// [kquery.d.ts]
+export const k: number;
+
+//// [package.json]
+{ "typings": "lquery" }
+
+//// [lquery.ts]
+export const l = 2;
+
+//// [a.ts]
+import { j } from "jquery";
+import { k } from "kquery";
+import { l } from "lquery";
+j + k + l;
+
+
+//// [lquery.js]
+"use strict";
+exports.l = 2;
+//// [a.js]
+"use strict";
+var jquery_1 = require("jquery");
+var kquery_1 = require("kquery");
+var lquery_1 = require("lquery");
+jquery_1.j + kquery_1.k + lquery_1.l;
diff --git a/tests/baselines/reference/typingsLookup4.symbols b/tests/baselines/reference/typingsLookup4.symbols
new file mode 100644
index 0000000000000..144548c645265
--- /dev/null
+++ b/tests/baselines/reference/typingsLookup4.symbols
@@ -0,0 +1,27 @@
+=== /a.ts ===
+import { j } from "jquery";
+>j : Symbol(j, Decl(a.ts, 0, 8))
+
+import { k } from "kquery";
+>k : Symbol(k, Decl(a.ts, 1, 8))
+
+import { l } from "lquery";
+>l : Symbol(l, Decl(a.ts, 2, 8))
+
+j + k + l;
+>j : Symbol(j, Decl(a.ts, 0, 8))
+>k : Symbol(k, Decl(a.ts, 1, 8))
+>l : Symbol(l, Decl(a.ts, 2, 8))
+
+=== /node_modules/@types/jquery/jquery.d.ts ===
+export const j: number;
+>j : Symbol(j, Decl(jquery.d.ts, 0, 12))
+
+=== /node_modules/@types/kquery/kquery.d.ts ===
+export const k: number;
+>k : Symbol(k, Decl(kquery.d.ts, 0, 12))
+
+=== /node_modules/@types/lquery/lquery.ts ===
+export const l = 2;
+>l : Symbol(l, Decl(lquery.ts, 0, 12))
+
diff --git a/tests/baselines/reference/typingsLookup4.trace.json b/tests/baselines/reference/typingsLookup4.trace.json
new file mode 100644
index 0000000000000..4bca8456f5846
--- /dev/null
+++ b/tests/baselines/reference/typingsLookup4.trace.json
@@ -0,0 +1,93 @@
+[
+    "======== Resolving module 'jquery' from '/a.ts'. ========",
+    "Module resolution kind is not specified, using 'NodeJs'.",
+    "Loading module 'jquery' from 'node_modules' folder.",
+    "File '/node_modules/jquery.ts' does not exist.",
+    "File '/node_modules/jquery.tsx' does not exist.",
+    "File '/node_modules/jquery.d.ts' does not exist.",
+    "File '/node_modules/jquery/package.json' does not exist.",
+    "File '/node_modules/jquery/index.ts' does not exist.",
+    "File '/node_modules/jquery/index.tsx' does not exist.",
+    "File '/node_modules/jquery/index.d.ts' does not exist.",
+    "File '/node_modules/@types/jquery.ts' does not exist.",
+    "File '/node_modules/@types/jquery.tsx' does not exist.",
+    "File '/node_modules/@types/jquery.d.ts' does not exist.",
+    "Found 'package.json' at '/node_modules/@types/jquery/package.json'.",
+    "'package.json' has 'typings' field 'jquery.d.ts' that references '/node_modules/@types/jquery/jquery.d.ts'.",
+    "File '/node_modules/@types/jquery/jquery.d.ts' exist - use it as a name resolution result.",
+    "Resolving real path for '/node_modules/@types/jquery/jquery.d.ts', result '/node_modules/@types/jquery/jquery.d.ts'",
+    "======== Module name 'jquery' was successfully resolved to '/node_modules/@types/jquery/jquery.d.ts'. ========",
+    "======== Resolving module 'kquery' from '/a.ts'. ========",
+    "Module resolution kind is not specified, using 'NodeJs'.",
+    "Loading module 'kquery' from 'node_modules' folder.",
+    "File '/node_modules/kquery.ts' does not exist.",
+    "File '/node_modules/kquery.tsx' does not exist.",
+    "File '/node_modules/kquery.d.ts' does not exist.",
+    "File '/node_modules/kquery/package.json' does not exist.",
+    "File '/node_modules/kquery/index.ts' does not exist.",
+    "File '/node_modules/kquery/index.tsx' does not exist.",
+    "File '/node_modules/kquery/index.d.ts' does not exist.",
+    "File '/node_modules/@types/kquery.ts' does not exist.",
+    "File '/node_modules/@types/kquery.tsx' does not exist.",
+    "File '/node_modules/@types/kquery.d.ts' does not exist.",
+    "Found 'package.json' at '/node_modules/@types/kquery/package.json'.",
+    "'package.json' has 'typings' field 'kquery' that references '/node_modules/@types/kquery/kquery'.",
+    "File '/node_modules/@types/kquery/kquery' does not exist.",
+    "File '/node_modules/@types/kquery/kquery.ts' does not exist.",
+    "File '/node_modules/@types/kquery/kquery.tsx' does not exist.",
+    "File '/node_modules/@types/kquery/kquery.d.ts' exist - use it as a name resolution result.",
+    "Resolving real path for '/node_modules/@types/kquery/kquery.d.ts', result '/node_modules/@types/kquery/kquery.d.ts'",
+    "======== Module name 'kquery' was successfully resolved to '/node_modules/@types/kquery/kquery.d.ts'. ========",
+    "======== Resolving module 'lquery' from '/a.ts'. ========",
+    "Module resolution kind is not specified, using 'NodeJs'.",
+    "Loading module 'lquery' from 'node_modules' folder.",
+    "File '/node_modules/lquery.ts' does not exist.",
+    "File '/node_modules/lquery.tsx' does not exist.",
+    "File '/node_modules/lquery.d.ts' does not exist.",
+    "File '/node_modules/lquery/package.json' does not exist.",
+    "File '/node_modules/lquery/index.ts' does not exist.",
+    "File '/node_modules/lquery/index.tsx' does not exist.",
+    "File '/node_modules/lquery/index.d.ts' does not exist.",
+    "File '/node_modules/@types/lquery.ts' does not exist.",
+    "File '/node_modules/@types/lquery.tsx' does not exist.",
+    "File '/node_modules/@types/lquery.d.ts' does not exist.",
+    "Found 'package.json' at '/node_modules/@types/lquery/package.json'.",
+    "'package.json' has 'typings' field 'lquery' that references '/node_modules/@types/lquery/lquery'.",
+    "File '/node_modules/@types/lquery/lquery' does not exist.",
+    "File '/node_modules/@types/lquery/lquery.ts' exist - use it as a name resolution result.",
+    "Resolving real path for '/node_modules/@types/lquery/lquery.ts', result '/node_modules/@types/lquery/lquery.ts'",
+    "======== Module name 'lquery' was successfully resolved to '/node_modules/@types/lquery/lquery.ts'. ========",
+    "======== Resolving type reference directive 'jquery', containing file '/__inferred type names__.ts', root directory '/node_modules/@types'. ========",
+    "Resolving with primary search path '/node_modules/@types'",
+    "Found 'package.json' at '/node_modules/@types/jquery/package.json'.",
+    "'package.json' has 'typings' field 'jquery.d.ts' that references '/node_modules/@types/jquery/jquery.d.ts'.",
+    "File '/node_modules/@types/jquery/jquery.d.ts' exist - use it as a name resolution result.",
+    "======== Type reference directive 'jquery' was successfully resolved to '/node_modules/@types/jquery/jquery.d.ts', primary: true. ========",
+    "======== Resolving type reference directive 'kquery', containing file '/__inferred type names__.ts', root directory '/node_modules/@types'. ========",
+    "Resolving with primary search path '/node_modules/@types'",
+    "Found 'package.json' at '/node_modules/@types/kquery/package.json'.",
+    "'package.json' has 'typings' field 'kquery' that references '/node_modules/@types/kquery/kquery'.",
+    "File '/node_modules/@types/kquery/kquery' does not exist.",
+    "File '/node_modules/@types/kquery/kquery.d.ts' exist - use it as a name resolution result.",
+    "======== Type reference directive 'kquery' was successfully resolved to '/node_modules/@types/kquery/kquery.d.ts', primary: true. ========",
+    "======== Resolving type reference directive 'lquery', containing file '/__inferred type names__.ts', root directory '/node_modules/@types'. ========",
+    "Resolving with primary search path '/node_modules/@types'",
+    "Found 'package.json' at '/node_modules/@types/lquery/package.json'.",
+    "'package.json' has 'typings' field 'lquery' that references '/node_modules/@types/lquery/lquery'.",
+    "File '/node_modules/@types/lquery/lquery' does not exist.",
+    "File '/node_modules/@types/lquery/lquery.d.ts' does not exist.",
+    "File '/node_modules/@types/lquery/index.d.ts' does not exist.",
+    "Looking up in 'node_modules' folder, initial location '/'",
+    "File '/node_modules/lquery.ts' does not exist.",
+    "File '/node_modules/lquery.d.ts' does not exist.",
+    "File '/node_modules/lquery/package.json' does not exist.",
+    "File '/node_modules/lquery/index.ts' does not exist.",
+    "File '/node_modules/lquery/index.d.ts' does not exist.",
+    "File '/node_modules/@types/lquery.ts' does not exist.",
+    "File '/node_modules/@types/lquery.d.ts' does not exist.",
+    "Found 'package.json' at '/node_modules/@types/lquery/package.json'.",
+    "'package.json' has 'typings' field 'lquery' that references '/node_modules/@types/lquery/lquery'.",
+    "File '/node_modules/@types/lquery/lquery' does not exist.",
+    "File '/node_modules/@types/lquery/lquery.ts' exist - use it as a name resolution result.",
+    "======== Type reference directive 'lquery' was successfully resolved to '/node_modules/@types/lquery/lquery.ts', primary: false. ========"
+]
\ No newline at end of file
diff --git a/tests/baselines/reference/typingsLookup4.types b/tests/baselines/reference/typingsLookup4.types
new file mode 100644
index 0000000000000..d922c7b1dfa53
--- /dev/null
+++ b/tests/baselines/reference/typingsLookup4.types
@@ -0,0 +1,30 @@
+=== /a.ts ===
+import { j } from "jquery";
+>j : number
+
+import { k } from "kquery";
+>k : number
+
+import { l } from "lquery";
+>l : number
+
+j + k + l;
+>j + k + l : number
+>j + k : number
+>j : number
+>k : number
+>l : number
+
+=== /node_modules/@types/jquery/jquery.d.ts ===
+export const j: number;
+>j : number
+
+=== /node_modules/@types/kquery/kquery.d.ts ===
+export const k: number;
+>k : number
+
+=== /node_modules/@types/lquery/lquery.ts ===
+export const l = 2;
+>l : number
+>2 : number
+
diff --git a/tests/cases/conformance/typings/typingsLookup4.ts b/tests/cases/conformance/typings/typingsLookup4.ts
new file mode 100644
index 0000000000000..234090aebad52
--- /dev/null
+++ b/tests/cases/conformance/typings/typingsLookup4.ts
@@ -0,0 +1,31 @@
+// @traceResolution: true
+// @noImplicitReferences: true
+// @currentDirectory: /
+// A file extension is optional in typings entries.
+
+// @filename: /tsconfig.json
+{}
+
+// @filename: /node_modules/@types/jquery/package.json
+{ "typings": "jquery.d.ts" }
+
+// @filename: /node_modules/@types/jquery/jquery.d.ts
+export const j: number;
+
+// @filename: /node_modules/@types/kquery/package.json
+{ "typings": "kquery" }
+
+// @filename: /node_modules/@types/kquery/kquery.d.ts
+export const k: number;
+
+// @filename: /node_modules/@types/lquery/package.json
+{ "typings": "lquery" }
+
+// @filename: /node_modules/@types/lquery/lquery.ts
+export const l = 2;
+
+// @filename: /a.ts
+import { j } from "jquery";
+import { k } from "kquery";
+import { l } from "lquery";
+j + k + l;