diff --git a/bash_completion b/bash_completion
new file mode 100644
index 0000000000..ac09e16e82
--- /dev/null
+++ b/bash_completion
@@ -0,0 +1,100 @@
+# Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# Add programmable completion to some Chromium OS build scripts
+
+
+# Look for "--arg=foo" or "--arg foo" (where foo can be an empty string) in the
+# word to be completed. If found, echo "--arg=foo".
+#
+_argeq()
+{
+  local arg=$1
+  local w0="${COMP_WORDS[COMP_CWORD]}"
+  local w1="${COMP_WORDS[COMP_CWORD-1]}"
+
+  # Check for completing "--arg="
+  if [ "${w1}" == ${arg} -a "${w0}" == "=" ]; then
+    echo "${w1}${w0}"
+    return 0
+  fi
+
+  # Check for completing "--arg foo"
+  if [ "${w1}" == ${arg} ]; then
+    echo "${w1}=${w0}"
+    return 0
+  fi
+
+  # Check for completing "--arg=foo"
+  if [ ${COMP_CWORD} -gt 2 ]; then
+    local w2="${COMP_WORDS[COMP_CWORD-2]}"
+    if [ "${w2}" == ${arg} -a "${w1}" == "=" ]; then
+      echo "${w2}${w1}${w0}"
+      return 0
+    fi
+  fi
+}
+
+
+# echo the existing target board sysroots
+#
+_board_sysroots()
+{
+  local builddir=/build
+  if [ ! -d ${builddir} ]; then
+    echo ""
+  else
+    echo $(command ls "${builddir}")
+  fi
+}
+
+# Completion for --board= argument for existing board sysroots
+#
+_board_sysroot()
+{
+  COMPREPLY=()
+  local arg=$(_argeq --board)
+  if [[ ${arg} == --board=* ]]; then
+    COMPREPLY=( $(compgen -W "$(_board_sysroots)" -- ${arg#--board=}) )
+    return 0
+  fi
+}
+
+complete -o bashdefault -o default -F _board_sysroot \
+  build_autotest.sh \
+  build_image \
+  build_packages \
+  image_to_usb
+
+
+# echo the existing target board overlays
+#
+_board_overlays()
+{
+  local overlaydir=../overlays
+  if [ ! -d ${overlaydir} ]; then
+    echo ""
+  else
+    echo $(command ls $overlaydir | grep overlay- | sed s,overlay-,,)
+  fi
+}
+
+# Completion for --board= argument for existing board overlays
+#
+_board_overlay()
+{
+  COMPREPLY=()
+  local arg=$(_argeq --board)
+  if [[ ${arg} == --board=* ]]; then
+    COMPREPLY=( $(compgen -W "$(_board_overlays)" -- ${arg#--board=}) )
+    return 0
+  fi
+}
+
+complete -o bashdefault -o default -F _board_overlay setup_board
+
+
+###  Local Variables:
+###  mode: shell-script
+###  End: