diff --git a/src/services/services.ts b/src/services/services.ts
index 5d702332853..87a31943c7b 100644
--- a/src/services/services.ts
+++ b/src/services/services.ts
@@ -2072,6 +2072,10 @@ module ts {
                         var moduleType = typeChecker.getTypeOfSymbol(importSymbol);
                         symbol = moduleType ? moduleType.symbol : undefined;
                     }
+                    // External module name in an ambient declaration
+                    else if (node.parent.kind === SyntaxKind.ModuleDeclaration) {
+                        symbol = typeChecker.getSymbolOfNode(node.parent);
+                    }
                     break;
             }
 
diff --git a/tests/cases/fourslash/goToDefinitionExternamModuleName5.ts b/tests/cases/fourslash/goToDefinitionExternamModuleName5.ts
new file mode 100644
index 00000000000..5a6596caccb
--- /dev/null
+++ b/tests/cases/fourslash/goToDefinitionExternamModuleName5.ts
@@ -0,0 +1,10 @@
+/// <reference path='fourslash.ts'/>
+
+// @Filename: a.ts
+/////*2*/declare module "external/*1*/" {
+////    class Foo { }
+////}
+
+goTo.marker('1');
+goTo.definition();
+verify.caretAtMarker('2');
\ No newline at end of file