diff --git a/completions/rbenv.bash b/completions/rbenv.bash
new file mode 100644
index 00000000..804ac2f2
--- /dev/null
+++ b/completions/rbenv.bash
@@ -0,0 +1,41 @@
+_commands()
+{
+    local cur commands
+    COMPREPLY=()
+    cur="${COMP_WORDS[COMP_CWORD]}"
+    commands="exec prefix rehash set-default set-local version versions\
+        whence which"
+
+    COMPREPLY=( $( compgen -W "${commands}" -- ${cur} ) )
+}
+
+_rubies()
+{
+    local cur rubies
+    local ROOT=$HOME/.rbenv/versions
+    COMPREPLY=()
+    cur=${COMP_WORDS[COMP_CWORD]}
+    rubies=($ROOT/*)
+    # remove all but the final part of the name
+    rubies="${rubies[@]##*/}"
+
+    COMPREPLY=( $( compgen -W "${rubies}" -- ${cur} ) )
+}
+
+_rbenv()
+{
+    local cur prev
+    COMPREPLY=()
+    cur="${COMP_WORDS[COMP_CWORD]}"
+    prev="${COMP_WORDS[COMP_CWORD-1]}"
+
+    if [[ "${prev}" == set-default ]]; then
+        _rubies
+    else
+        _commands
+    fi
+}
+
+complete -F _rbenv rbenv
+
+# vim: set ts=4 sw=4 tw=75 filetype=sh:
\ No newline at end of file