diff --git a/Misc/NEWS.d/next/Build/2024-05-07-21-15-47.gh-issue-118734.--GHiS.rst b/Misc/NEWS.d/next/Build/2024-05-07-21-15-47.gh-issue-118734.--GHiS.rst
new file mode 100644
index 00000000000..40e8e0615fe
--- /dev/null
+++ b/Misc/NEWS.d/next/Build/2024-05-07-21-15-47.gh-issue-118734.--GHiS.rst
@@ -0,0 +1,2 @@
+Fixes Windows build when invoked directly (not through the :file:`build.bat`
+script) without specifying a value for ``UseTIER2``.
diff --git a/PCbuild/_testinternalcapi.vcxproj b/PCbuild/_testinternalcapi.vcxproj
index d4cd8ad1a46..87db569423d 100644
--- a/PCbuild/_testinternalcapi.vcxproj
+++ b/PCbuild/_testinternalcapi.vcxproj
@@ -111,7 +111,7 @@
   <ItemDefinitionGroup>
     <ClCompile>
       <PreprocessorDefinitions Condition="'$(UseJIT)' == 'true'">_Py_JIT;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <PreprocessorDefinitions Condition="'$(UseTIER2)' != '0'">_Py_TIER2=$(UseTIER2);%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions Condition="'$(UseTIER2)' != '' and '$(UseTIER2)' != '0'">_Py_TIER2=$(UseTIER2);%(PreprocessorDefinitions)</PreprocessorDefinitions>
     </ClCompile>
   </ItemDefinitionGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
diff --git a/PCbuild/build.bat b/PCbuild/build.bat
index 13bd895694f..6c76f09a071 100644
--- a/PCbuild/build.bat
+++ b/PCbuild/build.bat
@@ -68,7 +68,7 @@ set verbose=/nologo /v:m /clp:summary
 set kill=
 set do_pgo=
 set pgo_job=-m test --pgo
-set UseTIER2=0
+set UseTIER2=
 
 :CheckOpts
 if "%~1"=="-h" goto Usage
diff --git a/PCbuild/pythoncore.vcxproj b/PCbuild/pythoncore.vcxproj
index b17e782a214..16fb424b11c 100644
--- a/PCbuild/pythoncore.vcxproj
+++ b/PCbuild/pythoncore.vcxproj
@@ -105,7 +105,7 @@
       <PreprocessorDefinitions>_USRDLL;Py_BUILD_CORE;Py_BUILD_CORE_BUILTIN;Py_ENABLE_SHARED;MS_DLL_ID="$(SysWinVer)";%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <PreprocessorDefinitions Condition="$(IncludeExternals)">_Py_HAVE_ZLIB;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <PreprocessorDefinitions Condition="'$(UseJIT)' == 'true'">_Py_JIT;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <PreprocessorDefinitions Condition="'$(UseTIER2)' != '0'">_Py_TIER2=$(UseTIER2);%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions Condition="'$(UseTIER2)' != '' and '$(UseTIER2)' != '0'">_Py_TIER2=$(UseTIER2);%(PreprocessorDefinitions)</PreprocessorDefinitions>
     </ClCompile>
     <Link>
       <AdditionalDependencies>version.lib;ws2_32.lib;pathcch.lib;bcrypt.lib;%(AdditionalDependencies)</AdditionalDependencies>