John Garnet Hathaway (born November 23, 1991) is an American professional ice hockey forward for the Philadelphia Flyers of the National Hockey League (NHL).

Hathaway was born in Naples, Florida, but moved to Kennebunkport, Maine with his family when he was six months old. He began playing hockey in Maine around the age of three with his older brother, and would practice at home when the pond by the family house froze over in the winter. In 1999, when he was seven years old, Hathaway and his family spent three months traveling around the world, a trip that his father John had planned to help "really give them the experience" of world travel.

Growing up, Hathaway and his older brother Ephraim were fans of the Washington Capitals of the National Hockey League (NHL), as their uncle, Greg Shove, had once worked with Capitals owner Ted Leonsis. Hathaway played hockey all four years at Phillips Academy Andover, a college-preparatory school in Andover, Massachusetts, where he played on a line with future New York Rangers skater Chris Kreider. Hathaway served as one of the Phillips Academy team captains during his senior season in 2010, and led the team in scoring with 37 points.

Mike Addesa, who coached Hathaway in the Hockey Night in Boston Elite Tournament in 2009, suggested that Mark White, the assistant coach for the Brown Bears men's ice hockey team, take a look at the player. While attending Brown University, Hathaway studied business, entrepreneurship and organizations. During the summer after his sophomore year, Hathaway and his Bears teammate Mike Juola purchased and operated a lobster roll cart.

Hathaway was part of a team of freshmen, also including Dennis Robertson, Matt Wahl, Marco de Filippo Roia, Mark Hourihan, and Jake Goldberg, that was expected to play a key role with the Bears in the 2010–11 season. He scored his first collegiate point on November 5, 2010, assisting David Brownschidle in the second period of a 3–3 tie against the Quinnipiac Bobcats. Hathaway later earned his first career goal in a 7–3 loss to Minnesota State at the 2011 Shillelagh Tournament championship game on January 2, 2011. At the end of the season, Hathaway was one of 23 Bears, including eight freshmen, named to the 2011 ECAC Hockey All-Academic Team, given to student-athletes with at least a 3.00 cumulative grade point average on a 4.00 scale.

As a sophomore during the 2011–12 season, Hathaway scored his first goal of the year on October 29, 2011, in a 3–2 victory over the Princeton Tigers. He missed six games due to illness, and finished the season with only three goals and five assists. On May 8, 2012, Hathaway was named one of four assistant captains for the Bears, and on June 26, he was named to the ECAC Hockey All-Academic Team for the second year in a row.

On May 14, 2014, Hathaway was awarded the Patrick S. Jones Memorial Trophy, a coaches' award given to the "member of the team who generates the most spark and enthusiasm in building team spirit". Across his collegiate hockey career, Hathaway totaled 58 points (20 goals and 38 assists) and 178 penalty minutes in 121 games with the Bears.

Following his junior year at Brown, Hathaway was invited to attend summer development camps with the Boston Bruins and Pittsburgh Penguins. On March 14, 2014, he signed a minor league deal with the Abbotsford Heat, the American Hockey League (AHL) affiliate of the Calgary Flames. Hathaway finished out the 2013–14 AHL season with the Heat, appearing in eight regular-season games and one playoff game. In his AHL debut, Hathaway fought with Jamie Devane, then with the Toronto Marlies.