diff --git a/tools/cpp/src/cpp-build/generate_geocoding_data.cc b/tools/cpp/src/cpp-build/generate_geocoding_data.cc
index 205947e831..1e628e2cd2 100644
--- a/tools/cpp/src/cpp-build/generate_geocoding_data.cc
+++ b/tools/cpp/src/cpp-build/generate_geocoding_data.cc
@@ -97,7 +97,8 @@ class DirEntry {
   DirEntryKinds kind_;
 };
 
-// Lists directory entries in path. "." and ".." are excluded. Returns true on
+// Lists directory entries in path. "." and ".." are excluded. Entries are
+// returned in a consistent order to ensure reproducibility. Returns true on
 // success.
 bool ListDirectory(const string& path, vector<DirEntry>* entries) {
   entries->clear();
@@ -135,6 +136,9 @@ bool ListDirectory(const string& path, vector<DirEntry>* entries) {
     }
     entries->push_back(DirEntry(entry->d_name, kind));
   }
+  std::sort(
+      entries->begin(), entries->end(),
+      [](const DirEntry& a, const DirEntry& b) { return a.name() < b.name(); });
 }
 
 // Returns true if s ends with suffix.