diff --git a/clang-tools-extra/clangd/FindTarget.cpp b/clang-tools-extra/clangd/FindTarget.cpp
--- a/clang-tools-extra/clangd/FindTarget.cpp
+++ b/clang-tools-extra/clangd/FindTarget.cpp
@@ -574,6 +574,10 @@
 }
 
 namespace {
+
+llvm::SmallVector<ReferenceLoc> refInTypeLoc(TypeLoc L,
+                                             const HeuristicResolver *Resolver);
+
 llvm::SmallVector<ReferenceLoc> refInDecl(const Decl *D,
                                           const HeuristicResolver *Resolver) {
   struct Visitor : ConstDeclVisitor<Visitor> {
@@ -610,6 +614,16 @@
                                   {D->getAliasedNamespace()}});
     }
 
+    void VisitEnumDecl(const EnumDecl *ED) {
+      VisitNamedDecl(ED);
+      // FIXME: Should RecursiveASTVisitor be visiting this TypeLoc instead? (It
+      // doesn't).
+      if (TypeSourceInfo *BaseType = ED->getIntegerTypeSourceInfo()) {
+        llvm::copy(refInTypeLoc(BaseType->getTypeLoc(), Resolver),
+                   std::back_inserter(Refs));
+      }
+    }
+
     void VisitNamedDecl(const NamedDecl *ND) {
       // We choose to ignore {Class, Function, Var, TypeAlias}TemplateDecls. As
       // as their underlying decls, covering the same range, will be visited.
diff --git a/clang-tools-extra/clangd/unittests/SemanticHighlightingTests.cpp b/clang-tools-extra/clangd/unittests/SemanticHighlightingTests.cpp
--- a/clang-tools-extra/clangd/unittests/SemanticHighlightingTests.cpp
+++ b/clang-tools-extra/clangd/unittests/SemanticHighlightingTests.cpp
@@ -729,6 +729,11 @@
           }
         };
       )cpp",
+      // Enum base specifier
+      R"cpp(
+        using $Primitive_decl[[MyTypedef]] = int;
+        enum $Enum_decl[[MyEnum]] : $Primitive[[MyTypedef]] {};
+      )cpp",
   };
   for (const auto &TestCase : TestCases)
     // Mask off scope modifiers to keep the tests manageable.