diff --git a/Misc/NEWS.d/next/Build/2025-09-03-14-55-59.gh-issue-138451.-Qzh2S.rst b/Misc/NEWS.d/next/Build/2025-09-03-14-55-59.gh-issue-138451.-Qzh2S.rst
new file mode 100644
index 00000000000000..46cc6ffc05ea2d
--- /dev/null
+++ b/Misc/NEWS.d/next/Build/2025-09-03-14-55-59.gh-issue-138451.-Qzh2S.rst
@@ -0,0 +1 @@
+Search for LLVM tools in ``LLVM_TOOLS_INSTALL_DIR`` during the build.
diff --git a/Tools/jit/_llvm.py b/Tools/jit/_llvm.py
index f09a8404871b24..b714b9d810f9e5 100644
--- a/Tools/jit/_llvm.py
+++ b/Tools/jit/_llvm.py
@@ -69,6 +69,11 @@ async def _get_brew_llvm_prefix(*, echo: bool = False) -> str | None:
 
 @_async_cache
 async def _find_tool(tool: str, *, echo: bool = False) -> str | None:
+    # Explicitly defined LLVM installation location
+    if llvm_tools_dir := os.getenv("LLVM_TOOLS_INSTALL_DIR"):
+        path = os.path.join(llvm_tools_dir, tool)
+        if await _check_tool_version(path, echo=echo):
+            return path
     # Unversioned executables:
     path = tool
     if await _check_tool_version(path, echo=echo):