diff --git a/cartographer/BUILD.bazel b/cartographer/BUILD.bazel
index a44d8a9..2cd30ee 100644
--- a/cartographer/BUILD.bazel
+++ b/cartographer/BUILD.bazel
@@ -64,6 +64,7 @@ cc_library(
     ] + glob([
         "**/*.h",
     ]),
+    copts = ["-Wno-sign-compare"],
     includes = ["."],
     deps = [
         ":cc_protos",
diff --git a/cartographer_grpc/BUILD.bazel b/cartographer_grpc/BUILD.bazel
index 5cf2b40..1c47b30 100644
--- a/cartographer_grpc/BUILD.bazel
+++ b/cartographer_grpc/BUILD.bazel
@@ -81,6 +81,7 @@ cc_library(
     hdrs = glob([
         "**/*.h",
     ]),
+    copts = ["-Wno-sign-compare"],
     includes = ["."],
     deps = [
         ":cc_protos",