John Mulaney: Baby J (stylised as John Mulaney: "Baby J") is a 2023 stand-up comedy film written by and starring John Mulaney. It was recorded in February 2023 at the Boston Symphony Hall and was released by Netflix on April 25, 2023. It is Mulaney's first stand-up special in five years, after Kid Gorgeous at Radio City (2018). The special consists of Mulaney recollecting his life experiences and escapades surrounding his drug addiction, including his intervention and subsequent rehabilitation.

The special received positive reviews from critics, who praised Mulaney’s storytelling, honesty and deconstruction of likability, though was criticized by some for the perceived shorthanded approach to the subject matter.For the special, Mulaney received the Outstanding Writing for a Variety Special at the 75th Emmy Awards, as well as the special as a whole being nominated for Outstanding Variety Special (Pre-Recorded)