BYOB or BYO is an initialism and acronym concerning wine or liquor ("bring your own bottle" or "bring your own booze"), beer ("bring your own beer"), or marijuana ("bring your own bud").
BYOB is stated on an invitation to indicate that the host will not be providing alcohol, and that guests should bring their own. Some restaurants and business establishments (especially in areas where liquor licenses are difficult to obtain) allow patrons to bring their own bottle, sometimes subject to opening fees or membership conditions (or because the establishment itself does not have license to sell alcohol).[citation needed]