diff --git a/clang-tools-extra/clangd/ClangdLSPServer.cpp b/clang-tools-extra/clangd/ClangdLSPServer.cpp
--- a/clang-tools-extra/clangd/ClangdLSPServer.cpp
+++ b/clang-tools-extra/clangd/ClangdLSPServer.cpp
@@ -555,7 +555,7 @@
        }},
       {"signatureHelpProvider",
        llvm::json::Object{
-           {"triggerCharacters", {"(", ","}},
+           {"triggerCharacters", {"(", ",", ")"}},
        }},
       {"declarationProvider", true},
       {"definitionProvider", true},
diff --git a/clang-tools-extra/clangd/test/initialize-params.test b/clang-tools-extra/clangd/test/initialize-params.test
--- a/clang-tools-extra/clangd/test/initialize-params.test
+++ b/clang-tools-extra/clangd/test/initialize-params.test
@@ -107,7 +107,8 @@
 # CHECK-NEXT:      "signatureHelpProvider": {
 # CHECK-NEXT:        "triggerCharacters": [
 # CHECK-NEXT:          "(",
-# CHECK-NEXT:          ","
+# CHECK-NEXT:          ",",
+# CHECK-NEXT:          ")"
 # CHECK-NEXT:        ]
 # CHECK-NEXT:      },
 # CHECK-NEXT:      "textDocumentSync": {