Zachary O'Brien (born June 28, 1992) is a Canadian professional ice hockey winger who currently plays for the Newfoundland Growlers in the ECHL while under contract to the Toronto Marlies of the American Hockey League (AHL). Prior to turning professional, O'Brien played three seasons with the Acadie–Bathurst Titan of the Quebec Major Junior Hockey League (QMJHL). During his time with the Titan, O'Brien won the Frank J. Selke Memorial Trophy as the league's most sportsmanlike player twice.