diff --git a/clang-tools-extra/clangd/Compiler.cpp b/clang-tools-extra/clangd/Compiler.cpp
--- a/clang-tools-extra/clangd/Compiler.cpp
+++ b/clang-tools-extra/clangd/Compiler.cpp
@@ -63,6 +63,7 @@
   // createInvocationFromCommandLine sets DisableFree.
   CI->getFrontendOpts().DisableFree = false;
   CI->getLangOpts()->CommentOpts.ParseAllComments = true;
+  CI->getLangOpts()->RetainCommentsFromSystemHeaders = true;
   return CI;
 }
 
diff --git a/clang-tools-extra/clangd/index/IndexAction.cpp b/clang-tools-extra/clangd/index/IndexAction.cpp
--- a/clang-tools-extra/clangd/index/IndexAction.cpp
+++ b/clang-tools-extra/clangd/index/IndexAction.cpp
@@ -160,6 +160,7 @@
   bool BeginInvocation(CompilerInstance &CI) override {
     // We want all comments, not just the doxygen ones.
     CI.getLangOpts().CommentOpts.ParseAllComments = true;
+    CI.getLangOpts().RetainCommentsFromSystemHeaders = true;
     // Index the whole file even if there are warnings and -Werror is set.
     // Avoids some analyses too. Set in two places as we're late to the party.
     CI.getDiagnosticOpts().IgnoreWarnings = true;