The 21-year-old from Kanata, Ont., became the first Clarkson University player to win the Patty Kazmaier Award that goes to the best player in NCAA Division 1 women's hockey.
Rattray helped lead the Golden Knights to their first Frozen Four appearance. They'll face the University of Minnesota on Sunday in the championship game.
"It's been unbelievable," Rattray told The Canadian Press after receiving the award Saturday. "Especially as a senior, there's nothing more I could ask for than to cap off my senior year playing in the last game of the season.
"It's my last college game. The first game ever I played in my career was against Minnesota and now the last one. It's going to be exciting (Sunday) and a lot of emotions, but you've got to go out there and play your game."
Rattray ranked second in NCAA scoring this season with 62 points — 28 goals and 34 assists in 39 games — to help Clarkson set a single-season record for wins with 30.
She's the fifth Canadian to win the Patty Kazmaier Award in its 17-year history.
Cornell forward Jillian Saulnier from Halifax and American forward Hannah Brandt of the University of Minnesota were the other two finalists for the award.
Brandt led Division 1 scoring with 22 goals and 41 assists for 63 points in 39 games. Saulnier, 22, ranked fourth with 28 goals and 28 assists in 34 games.
Previous Canadian winners of the award were Mercyhurst's Vicki Bendus of Wasaga Beach, Ont., (2010); Harvard's Sarah Vaillancourt of Sherbrooke, Que., (2008); Wisconsin's Sara Bauer of St. Catharines, Ont., (2006); and Harvard's Jennifer Botterill of Winnipeg (2001, 2003).
The award was established in 1998 in memory of Kazmaier, a Princeton defenceman who died of a blood disease at the age of 28.
"It's definitely a great honour and especially with those nominees," Rattray said. "It was kind of neat to be part of that group and it was neat to see at the banquet today what Patty was all about.
"I was pretty nervous at first, but then excitement kind of came over me. Definitely an honourable group to be part of."
Rattray, five foot six and 172 pounds, will graduate with a degree in business from Clarkson, which is located in Potsdam, N.Y. She had two assists in Clarkson's 5-1 win over Mercyhurst in Friday's Frozen Four semifinal.
Rattray is a prospect for the Canadian women's hockey team. She won silver and gold with Canada at the world under-18 women's hockey championship in 2009 and 2010 respectively. She then spent three years playing for Canada's under-22 team.