An ashtray is a receptacle for ash and butts from cigarettes and cigars. Ashtrays are typically made of fireproof material such as glass, heat-resistant plastic, pottery, metal, or rock.

The most common ashtray design is a shallow cylinder with a flat base, to rest on a table. Other ashtrays, particularly in public places, are wall mounted, and larger than standard tabletop ashtrays due to the increased use they receive. Many ashtrays have notches at the rim, to hold cigarettes and/or a cigar. In Spain, some ashtrays consist of two interlocking parts, the bottom of which is filled with water. Ashtrays are also often built into cars and dustbins, and provided in toilets and other public places.

Ashtrays have been a popular advertising vehicle. Collectors look for ashtrays with clever and unusual ads, colors, shapes and sizes. Some ashtrays of the late 1940s to early 1970s were freeform vehicles for Googie styling. During the 1950s and 1960s, small personal ashtrays were part of a table setting, commonly placed on the top right-hand side, behind the wine and water glasses.

Ashtrays in public places are becoming increasingly rare due to the proliferation of smoking bans. In addition, many vehicle manufacturers no longer include ashtrays as standard equipment, instead offering ashtrays and lighter plugs as optional accessories, typically dealer-installed. To fill this niche market, ashtrays which are designed to fit into an automobile's cup holders are now on the market.