diff --git a/clang-tools-extra/clangd/ClangdServer.cpp b/clang-tools-extra/clangd/ClangdServer.cpp
--- a/clang-tools-extra/clangd/ClangdServer.cpp
+++ b/clang-tools-extra/clangd/ClangdServer.cpp
@@ -673,8 +673,11 @@
 void ClangdServer::resolveTypeHierarchy(
     TypeHierarchyItem Item, int Resolve, TypeHierarchyDirection Direction,
     Callback<llvm::Optional<TypeHierarchyItem>> CB) {
-  clangd::resolveTypeHierarchy(Item, Resolve, Direction, Index);
-  CB(Item);
+  WorkScheduler.run(
+      "Resolve Type Hierarchy", "", [=, CB = std::move(CB)]() mutable {
+        clangd::resolveTypeHierarchy(Item, Resolve, Direction, Index);
+        CB(Item);
+      });
 }
 
 void ClangdServer::prepareCallHierarchy(