A mug is a type of cup typically used for drinking hot drinks, such as coffee, hot chocolate, or tea. Mugs usually have handles and hold a larger amount of fluid than other types of cups. Typically, a mug holds approximately 240–350 ml (8–12 US fl oz; 8.3–12.5 imp fl oz) of liquid. A mug is a less formal style of drink container and is not usually used in formal place settings, where a teacup or coffee cup is preferred. Shaving mugs are used to assist in wet shaving.

Ancient mugs were usually carved in wood or bone, made of ceramic, or shaped of clay, while most modern ones are made of ceramic materials such as bone china, earthenware, porcelain, or stoneware. Some are made from strengthened glass, such as Pyrex. Other materials, including enameled metal, plastic, or steel are preferred, when reduced weight or resistance to breakage is at a premium, such as for camping. A travel mug is insulated and has a cover with a small sipping opening to prevent spills. Techniques such as silk screen printing or decals are used to apply decorations such as logos or images and fan art, which are fired onto the mug to ensure permanence.