Index: clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
===================================================================
--- clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -1264,6 +1264,10 @@
   assert(!(isFriend && Owner->isDependentContext()));
   Inst->setPreviousDecl(PrevClassTemplate);
 
+  // Instantiate the attributes on both the template declaration and the associated record declaration.
+  SemaRef.InstantiateAttrsForDecl(TemplateArgs, Pattern, Inst, LateAttrs, StartingScope);
+  SemaRef.InstantiateAttrsForDecl(TemplateArgs, Pattern, RecordInst, LateAttrs, StartingScope);
+
   RecordInst->setDescribedClassTemplate(Inst);
 
   if (isFriend) {
@@ -1491,6 +1495,8 @@
   if (SubstQualifier(D, Record))
     return nullptr;
 
+  SemaRef.InstantiateAttrsForDecl(TemplateArgs, D, Record, LateAttrs, StartingScope);
+
   Record->setImplicit(D->isImplicit());
   // FIXME: Check against AS_none is an ugly hack to work around the issue that
   // the tag decls introduced by friend class declarations don't have an access
Index: clang/test/SemaCXX/PR38913.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaCXX/PR38913.cpp
@@ -0,0 +1,26 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -emit-llvm -o - %s | FileCheck %s
+
+// PR38913
+// Check that we instantiate attributes on declarations for...
+
+// ...a member class of a class template specialization
+template<class T> struct A { struct __attribute__((abi_tag("ATAG"))) X { }; };
+A<int>::X* a() { return 0; } // CHECK-DAG: @_Z1aB4ATAGv
+
+// ...a member class template
+template<class T> struct B { template<class U> struct __attribute__((abi_tag("BTAG"))) X { }; };
+B<int>::X<int>* b() { return 0; } // CHECK-DAG: @_Z1bB4BTAGv
+
+// ...a member partial specialization
+template<class T> struct C {
+  template<class U, class V> struct X { };
+  template<class V> struct __attribute__((abi_tag("CTAG"))) X<int, V> { };
+};
+C<int>::X<int, long>* c() { return 0; } // CHECK-DAG: @_Z1cB4CTAGv
+
+// ...a member explicit specialization
+template<class T> struct D {
+  template<class U> struct X { };
+  template<> struct __attribute__((abi_tag("DTAG"))) X<int> { };
+};
+D<int>::X<int>* d() { return 0; } // CHECK-DAG: @_Z1dB4DTAGv