diff --git a/clang-tools-extra/clangd/ClangdServer.h b/clang-tools-extra/clangd/ClangdServer.h
--- a/clang-tools-extra/clangd/ClangdServer.h
+++ b/clang-tools-extra/clangd/ClangdServer.h
@@ -185,10 +185,6 @@
     /// regions in the document.
     bool PublishInactiveRegions = false;
 
-    /// Whether to run preamble indexing asynchronously in an independent
-    /// thread.
-    bool AsyncPreambleIndexing = false;
-
     explicit operator TUScheduler::Options() const;
   };
   // Sensible default options for use in tests.
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
@@ -94,7 +94,7 @@
                              ASTCtx.getPreprocessor(), *CanonIncludes);
     };
 
-    if (Opts.AsyncPreambleIndexing && Tasks) {
+    if (Tasks) {
       Tasks->runAsync("Preamble indexing for:" + Path + Version,
                       std::move(Task));
     } else