Arjan Singh Āulakh (born August 12, 1974), known by the stage name Arj Barker, is an American comedian and actor from San Anselmo, California. He has toured in North America, Australia, New Zealand and Europe. He was born to an engineer father and artist mother. His father is of Indian Punjabi Sikh descent and his mother is of European descent.

Barker started his career in comedy after graduating from high school in 1989. His first gigs were at a café called Caffe Nuvo in downtown San Anselmo where he hosted stand-up night every Sunday throughout the early 1990s. Barker appeared on Premium Blend in 1997, followed by appearances on the shows Late Night with Conan O'Brien and The Glass House. He twice hosted Comedy Central Presents, first on September 20, 2000, and again on March 31, 2006. Barker was featured in Comedy Central's animated series Shorties Watchin' Shorties. He appeared on the Australian show Thank God You're Here on October 18, 2006, September 19, 2007, and June 17, 2009.

Barker co-wrote and performed in The Marijuana-Logues, an Off-Broadway show in New York City, with Doug Benson and Tony Camin. The title of the show was a parody of The Vagina Monologues. NBC gave Barker the lead role for sitcom Nearly Nirvana, originally scheduled for 2004. However, Barker was replaced in the lead role by the show's creator, Ajay Sahgal, and the show never aired

Barker appeared in the HBO sitcom Flight of the Conchords, playing Dave. Barker has been successful in Australia for a number of years since first appearing at the Melbourne International Comedy Festival in 2000, and presently resides there. At the ARIA Music Awards of 2019, he won Best Comedy Release for Organic.

During the 2024 Melbourne International Comedy Festival, Barker attracted widespread media attention in Australia for, while on stage in front of a live audience, demanding a mother breastfeeding her 7-month-old baby to leave and have her ticket refunded. Barker claimed the baby was interrupting his train of thought.