A bartender (also known as a barkeep or a mixologist) is a person who formulates and serves alcoholic or soft drink beverages behind the bar, usually in a licensed establishment as well as in restaurants and nightclubs, but also occasionally at private parties. Bartenders also usually maintain the supplies and inventory for the bar. As well as serving beer and wine, a bartender can generally also mix classic cocktails such as a Cosmopolitan, Manhattan, Old Fashioned, and Mojito.

Bartenders are also responsible for confirming that customers meet the legal drinking age requirements before serving them alcoholic beverages. In certain countries, such as the United States, Canada, the United Kingdom, Republic of Ireland and Sweden, bartenders are legally required to refuse more alcohol to drunk customers.