diff --git a/clang-tools-extra/clangd/XRefs.cpp b/clang-tools-extra/clangd/XRefs.cpp
--- a/clang-tools-extra/clangd/XRefs.cpp
+++ b/clang-tools-extra/clangd/XRefs.cpp
@@ -283,6 +283,30 @@
   // instead of failing.
   D = llvm::cast<NamedDecl>(D->getCanonicalDecl());
 
+  // Prefer C++ class definitions over a forward declaration.
+  if (const auto *TD = llvm::dyn_cast<TagDecl>(D)) {
+    if (const auto *Def = TD->getDefinition()) {
+      // Exception: forward decl is exposed in a header, definition is not.
+      // (This exception matches the spirit of our indexing heuristics).
+      if (/*PreferDef=*/[&] {
+        if (Def == TD)
+          return true;
+        const auto &SM = D->getASTContext().getSourceManager();
+        FileID DefFile = SM.getDecomposedExpansionLoc(Def->getLocation()).first;
+        if (DefFile != SM.getMainFileID())
+          return true; // definition is in a header.
+        FileID DeclFile = SM.getDecomposedExpansionLoc(D->getLocation()).first;
+        if (DefFile == DeclFile)
+          return true; // def/decl are equally visible.
+        // We've established that the definition is in the main file, and the
+        // decl is some other header.
+        return isHeaderFile(SM.getFileEntryRefForID(DefFile)->getName(),
+                            D->getASTContext().getLangOpts());
+      }())
+        D = Def;
+    }
+  }
+
   // Prefer Objective-C class/protocol definitions over the forward declaration.
   if (const auto *ID = dyn_cast<ObjCInterfaceDecl>(D))
     if (const auto *DefinitionID = ID->getDefinition())
diff --git a/clang-tools-extra/clangd/unittests/XRefsTests.cpp b/clang-tools-extra/clangd/unittests/XRefsTests.cpp
--- a/clang-tools-extra/clangd/unittests/XRefsTests.cpp
+++ b/clang-tools-extra/clangd/unittests/XRefsTests.cpp
@@ -568,8 +568,8 @@
       )cpp",
 
       R"cpp(// Forward class declaration
-        class $decl[[Foo]];
-        class $def[[Foo]] {};
+        class Foo;
+        class [[Foo]] {};
         F^oo* foo();
       )cpp",
 
@@ -1030,6 +1030,33 @@
     }
   }
 }
+
+TEST(LocateSymbol, TypeForwardDeclaredInHeader) {
+  Annotations Code(R"cpp(
+    class [[X]] {};
+    ^X *x;
+  )cpp");
+
+  TestTU TU;
+  TU.HeaderCode = "class X;";
+  TU.Code = Code.code();
+
+  auto AST = TU.build();
+  auto Index = TU.index();
+  LocatedSymbol S = locateSymbolAt(AST, Code.point(), Index.get()).front();
+  EXPECT_EQ(S.Name, "X");
+  auto Filename = [&](const Location &L) {
+    return llvm::sys::path::filename(L.uri.file());
+  };
+  EXPECT_EQ(Filename(S.PreferredDeclaration), TU.HeaderFilename);
+  EXPECT_EQ(Filename(*S.Definition), TU.Filename);
+
+  S = findType(AST, Code.point()).front();
+  EXPECT_EQ(S.Name, "X");
+  EXPECT_EQ(Filename(S.PreferredDeclaration), TU.HeaderFilename);
+  EXPECT_EQ(Filename(*S.Definition), TU.Filename);
+}
+
 TEST(LocateSymbol, ValidSymbolID) {
   auto T = Annotations(R"cpp(
     #define MACRO(x, y) ((x) + (y))