A smoking jacket is an item of clothing, now relatively rare, specifically designed for the purposes of smoking tobacco, usually in the form of pipes and cigars. While naturally styles vary, the classic smoking jacket is a waist-length jacket usually made of velvet or perhaps silk, with a shawl collar and turn-up cuffs and toggle fastenings. Usually they come in rich colours such as burgundy and bottle green.

The smoking jacket became a popular accessory in Victorian times, when it was believed that the sensitive and delicate nostrils of ladies would be assailed by the pungent fumes of tobacco clinging to everyday clothing. Consequently it became de rigueur for every considerate gentleman to don his smoking jacket before lighting his cigar or pipe, usually after dinner. Smoking caps were also sometimes worn for the same reason.

The comparative rarity of serious and dedicated pipe and cigar smoking as well as the vagaries of fashion mean that in today's world the smoking jacket is a rare item; the relatively high cost of quality items also militates against their widespread use. Other than vintage clothing stores a quality smoking jacket (which can, and frequently does, last a lifetime) would now usually have to be specially made by those few outfitters still in the habit of creating them.

In German, French, Brazilian Portuguese and Mexican Spanish, smoking has been adopted as a pseudo-loanword, but in reference to what in English is known as a dinner jacket or tuxedo.