diff --git a/src/harness/fourslash.ts b/src/harness/fourslash.ts
index 4bb2ba69b0..c41418cbbb 100644
--- a/src/harness/fourslash.ts
+++ b/src/harness/fourslash.ts
@@ -4557,6 +4557,7 @@ namespace FourSlashInterface {
                 switch (keyword.name) {
                     case "enum":
                     case "interface":
+                    case "implements":
                     case "private":
                     case "protected":
                     case "public":
diff --git a/src/services/completions.ts b/src/services/completions.ts
index b3da8c2874..af8a043022 100644
--- a/src/services/completions.ts
+++ b/src/services/completions.ts
@@ -1989,6 +1989,7 @@ namespace ts.Completions {
             case SyntaxKind.DeclareKeyword:
             case SyntaxKind.EnumKeyword:
             case SyntaxKind.GlobalKeyword:
+            case SyntaxKind.ImplementsKeyword:
             case SyntaxKind.InferKeyword:
             case SyntaxKind.InterfaceKeyword:
             case SyntaxKind.IsKeyword: