Tim O'Brien (born 28 March 1994) is a professional Australian rules footballer who plays for the Western Bulldogs in the Australian Football League (AFL).
Hawthorn selected O'Brien with pick 28 in the 2012 AFL Draft. He spent 2013 developing in the VFL playing for Hawthorn's reserve affiliate side, the Box Hill Hawks, and was a member of their premiership winning side.
On August 22, 2017, after having a career-best season, O'Brien signed a two-year contract extension keeping him at Hawthorn until the end of 2019.