Pajamas, also spelled pyjamas (see also spelling differences) and often shortened to PJs. The original paijama are loose, lightweight trousers fitted with drawstring waistbands and worn in South and West Asia by both sexes. In many English-speaking nations, pajamas are loose-fitting, two-piece garments derived from the original garment and worn chiefly for sleeping, but sometimes also for lounging, also by both sexes. More generally, pajamas may refer to several garments, for both daywear and nightwear, derived from traditional pajamas and involving variations of style and material.

The word "pyjama" or "pajama", which originally derives from the Persian word پايجامه (Peyjama meaning "leg garment"), was incorporated into the English language during British Raj through the Hindustani (the progenitor language of modern-day Urdu and Hindi).

Muslim girl, India, in paijama and kurti, 1844.

Girl in short sleeve PJs; doll in traditional.

Boys in stretch-knit pajamas.

Toddler in footed pajamas.

Traditional pajamas consist of a jacket-and-trousers combination made of soft fabric, such as flannel; the jacket has a placket front and its sleeves have no cuffs. In colloquial speech, these are called PJs, jim jams, or jammies; in South Asia, and sometimes in South Africa, they are known as night suits.