diff --git a/runtime/cmake/LibompDefinitions.cmake b/runtime/cmake/LibompDefinitions.cmake
index c3e3427a61d806fb9497dfa30940e740d5862069..c4cfbb9414133ac05b4c966db82f4aa8e4d4cbe8 100644
--- a/runtime/cmake/LibompDefinitions.cmake
+++ b/runtime/cmake/LibompDefinitions.cmake
@@ -21,8 +21,6 @@ function(libomp_get_definitions_flags cppflags)
     libomp_append(cppflags_local "-D _USRDLL")
     libomp_append(cppflags_local "-D _ITERATOR_DEBUG_LEVEL=0" IF_TRUE DEBUG_BUILD)
     libomp_append(cppflags_local "-D _DEBUG" IF_TRUE DEBUG_BUILD)
-    libomp_append(cppflags_local "-UUNICODE")
-    libomp_append(cppflags_local "-U_UNICODE")
   else()
     libomp_append(cppflags_local "-D _GNU_SOURCE")
     libomp_append(cppflags_local "-D _REENTRANT")
diff --git a/runtime/src/CMakeLists.txt b/runtime/src/CMakeLists.txt
index 57d7c2f15f6f667efa6500831ed8f007efd58bc5..777434da447f01ff398a355e8f0d2ca129678350 100644
--- a/runtime/src/CMakeLists.txt
+++ b/runtime/src/CMakeLists.txt
@@ -31,6 +31,11 @@ add_custom_command(
 )
 
 # Set the -D definitions for all sources
+# UNICODE and _UNICODE are set in LLVM's CMake system.  They affect the
+# ittnotify code and should only be set when compiling ittnotify_static.c
+# on Windows (done below).
+# TODO: Fix the UNICODE usage in ittnotify code for Windows.
+remove_definitions(-DUNICODE -D_UNICODE)
 libomp_get_definitions_flags(LIBOMP_CONFIGURED_DEFINITIONS_FLAGS)
 add_definitions(${LIBOMP_CONFIGURED_DEFINITIONS_FLAGS})
 
@@ -192,7 +197,7 @@ if(WIN32)
   libomp_append(LIBOMP_MASM_DEFINITIONS "-DOMPT_SUPPORT" IF_TRUE_1_0 LIBOMP_OMPT_SUPPORT)
   libomp_list_to_string("${LIBOMP_MASM_DEFINITIONS}" LIBOMP_MASM_DEFINITIONS)
   set_property(SOURCE z_Windows_NT-586_asm.asm APPEND_STRING PROPERTY COMPILE_FLAGS " ${LIBOMP_MASM_DEFINITIONS}")
-  #set_source_files_properties(thirdparty/ittnotify/ittnotify_static.c PROPERTIES COMPILE_DEFINITIONS "UNICODE")
+  set_source_files_properties(thirdparty/ittnotify/ittnotify_static.c PROPERTIES COMPILE_DEFINITIONS "UNICODE")
 
   # Create Windows import library
   # the import library is "re-linked" to include kmp_import.c which prevents
diff --git a/runtime/src/thirdparty/ittnotify/ittnotify_static.c b/runtime/src/thirdparty/ittnotify/ittnotify_static.c
index f84512d2126b11b3d4b19704eb295a72b14db7ab..5f365730eaca4bcdf8bb072766e43077c080b12b 100644
--- a/runtime/src/thirdparty/ittnotify/ittnotify_static.c
+++ b/runtime/src/thirdparty/ittnotify/ittnotify_static.c
@@ -8,11 +8,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-#if ITT_PLATFORM==ITT_PLATFORM_WIN
-#define UNICODE
-#define _UNICODE
-#endif
-
 #include "kmp_config.h"
 #include "ittnotify_config.h"