An evolution of the angarkha and the chapkan, the achkan is a knee-length upper garment with long sleeves, side slits and a standing collar that originated in the middle of the 19th century. It is significant for being the first Indian garment for men to prominently feature buttons and buttonholes.

According to some scholars, the invention of the achkan can be credited to the court of Oudh in Lucknow. It is likely to have evolved as a result of the European stitching popularised in the royal courts by British officers, resulting in a garment which was a hybrid of the angarkha and the European coat. The achkan is similar to an angarkha, with a waist seam, cloth panels and an extension called the balabar, which fits under the right hand side of the skirt of the garment and holds it in place. However, unlike the angarkha, its bodice is front-open and fastened over the torso using buttons.

Another garment closely linked and often confused with the achkan is the sherwani. However, the achkan is different from the sherwani in several aspects. As compared to the sherwani, it varies in length, has no lining and features a waist seam as well as gussets at the sleeves. Furthermore, the achkan was popular in the northern states as compared to the sherwani, which was more prevalent in South India, where the Mughal influence still lingered. Both the achkan and the sherwani have been credited with inspiring the Nehru jacket.

Black and white photograph of Jawaharlal Nehru and Finnish Foreign Minister Johannes Virolainen, by UA Saarinen
Jawaharlal Nehru (in achkan) and Finnish Foreign Minister Johannes Virolainen; UA Saarinen; 1957; Photograph: Finnish Heritage Agency, Wikimedia Commons
Photograph showing a white silk achkan with red and tiny blue motifs
Achkan; Lucknow, India; 1900–1935; Silk; Lucknow Bioscope, Uttar Pradesh, and Google Arts & Culture
Black and white photograph of SN Sinha, Jawaharlal Nehru, Eleanor Roosevelt and GV Mavlankar at the Parliament House in New Delhi
Indian politicians (L–R) SN Sinha, Jawaharlal Nehru, and GV Mavlankar (all wearing achkans) with Eleanor Roosevelt at the Parliament House ; New Delhi, India; 1952; US National Archives, United States, and Google Arts & Culture

The achkan can be worn with either a chudidaar or pyjama as the lower garment. Over time, it has become a garment that is primarily worn at formal events, especially weddings, in northern and western India.