diff --git a/src/compiler/moduleNameResolver.ts b/src/compiler/moduleNameResolver.ts
index 1cc11acd32d..018bddd420b 100644
--- a/src/compiler/moduleNameResolver.ts
+++ b/src/compiler/moduleNameResolver.ts
@@ -1097,13 +1097,18 @@ namespace ts {
     export function getPackageNameFromAtTypesDirectory(mangledName: string): string {
         const withoutAtTypePrefix = removePrefix(mangledName, "@types/");
         if (withoutAtTypePrefix !== mangledName) {
-            return stringContains(withoutAtTypePrefix, mangledScopedPackageSeparator) ?
-                "@" + withoutAtTypePrefix.replace(mangledScopedPackageSeparator, ts.directorySeparator) :
-                withoutAtTypePrefix;
+            return getUnmangledNameForScopedPackage(withoutAtTypePrefix);
         }
         return mangledName;
     }
 
+    /* @internal */
+    export function getUnmangledNameForScopedPackage(typesPackageName: string): string {
+        return stringContains(typesPackageName, mangledScopedPackageSeparator) ?
+            "@" + typesPackageName.replace(mangledScopedPackageSeparator, ts.directorySeparator) :
+            typesPackageName;
+    }
+
     function tryFindNonRelativeModuleNameInCache(cache: PerModuleNameCache | undefined, moduleName: string, containingDirectory: string, traceEnabled: boolean, host: ModuleResolutionHost): SearchResult<Resolved> {
         const result = cache && cache.get(containingDirectory);
         if (result) {
diff --git a/src/services/pathCompletions.ts b/src/services/pathCompletions.ts
index 65d288e7f8d..8840919c329 100644
--- a/src/services/pathCompletions.ts
+++ b/src/services/pathCompletions.ts
@@ -314,9 +314,11 @@ namespace ts.Completions.PathCompletions {
 
     function getCompletionEntriesFromTypings(host: LanguageServiceHost, options: CompilerOptions, scriptPath: string, span: TextSpan, result: CompletionEntry[] = []): CompletionEntry[] {
         // Check for typings specified in compiler options
+        const seen = createMap<true>();
         if (options.types) {
-            for (const moduleName of options.types) {
-                result.push(createCompletionEntryForModule(moduleName, ScriptElementKind.externalModuleName, span));
+            for (const typesName of options.types) {
+                const moduleName = getUnmangledNameForScopedPackage(typesName);
+                pushResult(moduleName);
             }
         }
         else if (host.getDirectories) {
@@ -328,32 +330,40 @@ namespace ts.Completions.PathCompletions {
 
             if (typeRoots) {
                 for (const root of typeRoots) {
-                    getCompletionEntriesFromDirectories(host, root, span, result);
+                    getCompletionEntriesFromDirectories(root);
                 }
             }
-        }
 
-        if (host.getDirectories) {
             // Also get all @types typings installed in visible node_modules directories
             for (const packageJson of findPackageJsons(scriptPath, host)) {
                 const typesDir = combinePaths(getDirectoryPath(packageJson), "node_modules/@types");
-                getCompletionEntriesFromDirectories(host, typesDir, span, result);
+                getCompletionEntriesFromDirectories(typesDir);
             }
         }
 
         return result;
-    }
 
-    function getCompletionEntriesFromDirectories(host: LanguageServiceHost, directory: string, span: TextSpan, result: Push<CompletionEntry>) {
-        if (host.getDirectories && tryDirectoryExists(host, directory)) {
-            const directories = tryGetDirectories(host, directory);
-            if (directories) {
-                for (let typeDirectory of directories) {
-                    typeDirectory = normalizePath(typeDirectory);
-                    result.push(createCompletionEntryForModule(getBaseFileName(typeDirectory), ScriptElementKind.externalModuleName, span));
+        function getCompletionEntriesFromDirectories(directory: string) {
+            Debug.assert(!!host.getDirectories);
+            if (tryDirectoryExists(host, directory)) {
+                const directories = tryGetDirectories(host, directory);
+                if (directories) {
+                    for (let typeDirectory of directories) {
+                        typeDirectory = normalizePath(typeDirectory);
+                        const directoryName = getBaseFileName(typeDirectory);
+                        const moduleName = getUnmangledNameForScopedPackage(directoryName);
+                        pushResult(moduleName);
+                    }
                 }
             }
         }
+
+        function pushResult(moduleName: string) {
+            if (!seen.has(moduleName)) {
+                result.push(createCompletionEntryForModule(moduleName, ScriptElementKind.externalModuleName, span));
+                seen.set(moduleName, true);
+            }
+        }
     }
 
     function findPackageJsons(directory: string, host: LanguageServiceHost): string[] {
diff --git a/tests/cases/fourslash/completionListInImportClause05.ts b/tests/cases/fourslash/completionListInImportClause05.ts
new file mode 100644
index 00000000000..f7b5244d5a4
--- /dev/null
+++ b/tests/cases/fourslash/completionListInImportClause05.ts
@@ -0,0 +1,20 @@
+/// <reference path='fourslash.ts' />
+
+// @Filename: app.ts
+////import * as A from "[|/*1*/|]";
+
+// @Filename: /node_modules/@types/a__b/index.d.ts
+////declare module "@e/f" { function fun(): string; }
+
+// @Filename: /node_modules/@types/c__d/index.d.ts
+////export declare let x: number;
+
+// NOTE: The node_modules folder is in "/", rather than ".", because it requires
+// less scaffolding to mock.  In particular, "/" is where we look for type roots.
+
+const [replacementSpan] = test.ranges();
+verify.completionsAt("1", [
+    { name: "@a/b", replacementSpan },
+    { name: "@c/d", replacementSpan },
+    { name: "@e/f", replacementSpan },
+]);
diff --git a/tests/cases/fourslash/completionListInImportClause06.ts b/tests/cases/fourslash/completionListInImportClause06.ts
new file mode 100644
index 00000000000..f6cfefa437f
--- /dev/null
+++ b/tests/cases/fourslash/completionListInImportClause06.ts
@@ -0,0 +1,17 @@
+/// <reference path='fourslash.ts' />
+
+// @typeRoots: T1,T2
+
+// @Filename: app.ts
+////import * as A from "[|/*1*/|]";
+
+// @Filename: T1/a__b/index.d.ts
+////export declare let x: number;
+
+// @Filename: T2/a__b/index.d.ts
+////export declare let x: number;
+
+// Confirm that entries are de-dup'd.
+verify.completionsAt("1", [
+    { name: "@a/b", replacementSpan: test.ranges()[0] },
+]);