diff --git a/tools/tox-venv b/tools/tox-venv
index 469e74c1..32a16851 100755
--- a/tools/tox-venv
+++ b/tools/tox-venv
@@ -1,30 +1,80 @@
 #!/bin/sh
+# vi: ts=4 expandtab
 
 error() { echo "$@" 1>&2; }
 fail() { [ $# -eq 0 ] || error "$@"; exit 1; }
-Usage() {
-   cat <<EOF
-Usage: ${0##*/} tox-environment [command [args]]
-   run command with provided arguments in the provided tox environment
-   command defaults to \${SHELL:-/bin/sh}.
-EOF
+list_environments() {
+    local tox_d="$1" tox_ini="$2" prefix="  "
+    envs=$(tox -c "$tox_ini" --listenvs) || return 1
+    ( 
+        cd "$tox_d" &&
+        for d in ${envs}; do
+            [ -f "$d/bin/activate" ] && s="*" || s=""
+            echo "${prefix}$d$s";
+        done
+    )
 }
 
-[ $# -eq 0 ] && { Usage 1>&2; exit 1; }
-[ "$1" = "-h" -o "$1" = "--help" ] && { Usage; exit 0; }
+Usage() {
+    local tox_d="$1" tox_ini="$2"
+    cat <<EOF
+Usage: ${0##*/} [--no-create] tox-environment [command [args]]
+   run command with provided arguments in the provided tox environment
+   command defaults to \${SHELL:-/bin/sh}.
+
+   run with '--list' to show available environments
+EOF
+    if [ -d "$tox_d" -a -f "$tox_ini" ]; then
+        echo
+        echo "existing environments in $tox_d"
+        list_environments "$tox_d" "$tox_ini"
+    fi
+}
+
+if [ -f tox.ini -a -d .tox ]; then
+    tox_d="./.tox"
+    tox_ini="$PWD/tox.ini"
+else
+    tox_d="${0%/*}/../.tox"
+    tox_ini="${0%/*}/../tox.ini"
+fi
+
+[ $# -eq 0 ] && { Usage "$tox_d" "$tox_ini" 1>&2; exit 1; }
+[ "$1" = "-h" -o "$1" = "--help" ] && { Usage "$tox_d" "$tox_ini"; exit 0; }
+
+[ -d "$tox_d" ] || fail "$tox_d: not a dir. maybe run 'tox'?"
+[ -f "$tox_ini" ] || fail "$tox_ini: did not find tox.ini"
+
+if [ "$1" = "-l" -o "$1" = "--list" ]; then
+    list_environments "$tox_d" "$tox_ini"
+    exit
+fi
+
+nocreate="false"
+if [ "$1" = "--no-create" ]; then
+    nocreate="true"
+    shift
+fi
 
 env="$1"
 shift
-tox_d="${0%/*}/../.tox"
 activate="$tox_d/$env/bin/activate"
 
-[ -d "$tox_d" ] || fail "$tox_d: not a dir. maybe run 'tox'?"
 if [ ! -f "$activate" ]; then
-   error "$env: not a valid tox environment?"
-   error "try one of:"
-   ( cd "$tox_d" &&
-     for d in *; do [ -f "$d/bin/activate" ] && error "  $d"; done )
-   fail
+    if $nocreate; then
+        fail "tox env '$env' did not exist, and no-create specified"
+    elif list_environments "$tox_d" "$tox_ini" | grep -q " $env$"; then
+        error "attempting to create $env:"
+        error "    tox -c $tox_ini --recreate --notest -e $env"
+        tox -c "$tox_ini" --recreate --notest -e "$env" ||
+            fail "failed creation of env $env"
+    else
+        error "$env: not a valid tox environment?"
+        error "found tox_d=$tox_d"
+        error "try one of:"
+        list_environments "$tox_d" "$tox_ini" 1>&2
+        fail
+    fi
 fi
 . "$activate"