diff --git a/tools/remote_build/linux.bazelrc b/tools/remote_build/linux.bazelrc
index 374903a0e42..dd78d51fd55 100644
--- a/tools/remote_build/linux.bazelrc
+++ b/tools/remote_build/linux.bazelrc
@@ -62,6 +62,10 @@ build:msan --action_env=LD_LIBRARY_PATH=/usr/local/libcxx-msan/lib
 # the version having https://github.com/googleapis/google-cloud-cpp/pull/14151
 build:msan --cxxopt='-std=c++17'
 build:msan --host_cxxopt='-std=c++17'
+# Attempt to fix flakes on MSAN thought to be related to MSAN being too slow
+# in unoptimized builds.
+build:msan --copt=-O1
+build:msan --cxxopt=-O1
 
 # thread sanitizer: most settings are already in %workspace%/.bazelrc
 # we only need a few additional ones that are Foundry specific
@@ -98,4 +102,4 @@ build:ubsan --action_env=LD_LIBRARY_PATH=/usr/local/libcxx-msan/lib
 # TODO(veblush): Remove the following after upgrading cloud-cpp-cloud to
 # the version having https://github.com/googleapis/google-cloud-cpp/pull/14151
 build:ubsan --cxxopt='-std=c++17'
-build:ubsan --host_cxxopt='-std=c++17'
\ No newline at end of file
+build:ubsan --host_cxxopt='-std=c++17'