diff --git a/clang-tools-extra/clangd/TidyProvider.cpp b/clang-tools-extra/clangd/TidyProvider.cpp
--- a/clang-tools-extra/clangd/TidyProvider.cpp
+++ b/clang-tools-extra/clangd/TidyProvider.cpp
@@ -106,7 +106,7 @@
     llvm::SmallVector<DotClangTidyCache *> Caches;
     {
       std::lock_guard<std::mutex> Lock(Mu);
-      for (auto I = path::begin(Parent), E = path::end(Parent); I != E; ++I) {
+      for (auto I = path::rbegin(Parent), E = path::rend(Parent); I != E; ++I) {
         assert(I->end() >= Parent.begin() && I->end() <= Parent.end() &&
                "Canonical path components should be substrings");
         llvm::StringRef Ancestor(Parent.begin(), I->end() - Parent.begin());
diff --git a/clang-tools-extra/clangd/unittests/CMakeLists.txt b/clang-tools-extra/clangd/unittests/CMakeLists.txt
--- a/clang-tools-extra/clangd/unittests/CMakeLists.txt
+++ b/clang-tools-extra/clangd/unittests/CMakeLists.txt
@@ -93,6 +93,7 @@
   TestIndex.cpp
   TestTU.cpp
   TestWorkspace.cpp
+  TidyProviderTests.cpp
   TypeHierarchyTests.cpp
   URITests.cpp
   XRefsTests.cpp
diff --git a/clang-tools-extra/clangd/unittests/TidyProviderTests.cpp b/clang-tools-extra/clangd/unittests/TidyProviderTests.cpp
new file mode 100644
--- /dev/null
+++ b/clang-tools-extra/clangd/unittests/TidyProviderTests.cpp
@@ -0,0 +1,60 @@
+//===-- TidyProviderTests.cpp - Clang tidy configuration provider tests ---===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "TestFS.h"
+#include "TidyProvider.h"
+#include "gtest/gtest.h"
+
+namespace clang {
+namespace clangd {
+
+namespace {
+
+TEST(TidyProvider, NestedDirectories) {
+  MockFS FS;
+  FS.Files[testPath(".clang-tidy")] = R"yaml(
+  Checks: 'llvm-*'
+  CheckOptions:
+    - key: TestKey
+      value: 1
+)yaml";
+  FS.Files[testPath("sub1/.clang-tidy")] = R"yaml(
+  Checks: 'misc-*'
+  CheckOptions:
+    - key: TestKey
+      value: 2
+)yaml";
+  FS.Files[testPath("sub1/sub2/.clang-tidy")] = R"yaml(
+  Checks: 'bugprone-*'
+  CheckOptions:
+    - key: TestKey
+      value: 3
+  InheritParentConfig: true
+)yaml";
+
+  TidyProvider Provider = provideClangTidyFiles(FS);
+
+  auto BaseOptions = getTidyOptionsForFile(Provider, testPath("File.cpp"));
+  ASSERT_TRUE(BaseOptions.Checks.hasValue());
+  EXPECT_EQ(*BaseOptions.Checks, "llvm-*");
+  EXPECT_EQ(BaseOptions.CheckOptions.lookup("TestKey").Value, "1");
+
+  auto Sub1Options = getTidyOptionsForFile(Provider, testPath("sub1/File.cpp"));
+  ASSERT_TRUE(Sub1Options.Checks.hasValue());
+  EXPECT_EQ(*Sub1Options.Checks, "misc-*");
+  EXPECT_EQ(Sub1Options.CheckOptions.lookup("TestKey").Value, "2");
+
+  auto Sub2Options =
+      getTidyOptionsForFile(Provider, testPath("sub1/sub2/File.cpp"));
+  ASSERT_TRUE(Sub2Options.Checks.hasValue());
+  EXPECT_EQ(*Sub2Options.Checks, "misc-*,bugprone-*");
+  EXPECT_EQ(Sub2Options.CheckOptions.lookup("TestKey").Value, "3");
+}
+} // namespace
+} // namespace clangd
+} // namespace clang