diff --git a/update_kernel.sh b/update_kernel.sh
index e0b428c1e4..7f48e5d63a 100755
--- a/update_kernel.sh
+++ b/update_kernel.sh
@@ -95,6 +95,16 @@ copy_kernelimage() {
   remote_sh dd if=/tmp/new_kern.bin of="${FLAGS_partition}"
 }
 
+check_kernelbuildtime() {
+  local version=$(readlink "/build/${FLAGS_board}/boot/vmlinuz" | cut -d- -f2-)
+  local build_dir="/build/${FLAGS_board}/lib/modules/${version}/build"
+  if [ "${build_dir}/Makefile" -nt "/build/${FLAGS_board}/boot/vmlinuz" ]; then
+    warn "Your build directory has been built more recently than"
+    warn "the installed kernel being updated to.  Did you forget to"
+    warn "run 'cros_workon_make chromeos-kernel --install'?"
+  fi
+}
+
 main() {
   trap cleanup EXIT
 
@@ -114,6 +124,8 @@ main() {
 
   old_kernel="${REMOTE_OUT}"
 
+  check_kernelbuildtime
+
   make_kernelimage
 
   if [[ ${REMOTE_VERITY} -eq ${FLAGS_FALSE} ]]; then