The 31-year-old forward from Toronto follows forward Sarah Vaillancourt of Sherbrooke, Que., and goaltender Kim St-Pierre of Chateauguay, Que., who also announced their retirements over the last week.
Vaillancourt's decision was unexpected because she played for Canada in the women's world hockey championship in Ottawa earlier this month.
But St-Pierre and Piper haven't played for Canada since the 2011 world championship. St. Pierre, 34, took a season off to have a baby and Piper finished her education degree. Neither player was named to Canada's roster for this year's world championship.
Piper indicated she would retire when she announced earlier this season that it would be her last with the Brampton Thunder of the Canadian Women's Hockey League.
"I've been thinking about it for a little while now," Piper told The Canadian Press. "This season confirmed it for me. I still love the game, but your body hurts a little more at the end of weekend games and I've had a lot of little injuries over the last few years.
"I've given a large portion of my life to the sport. It's time to be active in the sport in another way and not necessarily playing."
With Hockey Canada about to announce the roster of 27 players who will try out for the 2014 Winter Olympics, St-Pierre and Piper had to make a decision on their hockey future.
"We wanted to give them the time to think through it," said Kalli Quinn, Hockey Canada's director of female hockey. "We gave them that time through worlds. We're in a position where we're going to be announcing our centralization roster."
Piper won Olympic gold in 2002, 2006 and 2010. She is the eighth player from Canada's victorious 2010 squad to retire since those Winter Games in Vancouver and Whistler, B.C.
The others are St-Pierre, Vaillancourt, defenders Colleen Sostorics, Becky Kellar and Carla MacLeod and forwards Jennifer Botterill and Gina Kingsbury.
Piper had five goals and five assists in five games en route to gold in Vancouver.
"The atmosphere and the energy in that building was like having an extra person on the ice," Piper recalled. "To have the opportunity as an Olympian to play in your own country, there's just nothing better than that."
Piper's career totals for Canada were 40 goals and 78 assists in 111 career games over 12 seasons.
A powerful skater and smart playmaker, she was second in team scoring behind Hayley Wickenheiser at the 2006 Winter Olympics in Turin, Italy, with seven goals and eight assists in just five games.
But the four years between 2006 and 2010 were difficult for Piper. She suffered a major knee injury playing college hockey that kept her out of the 2007 world championship. Her father Alan died of a heart attack in 2008.
She was left off the world championship team in 2009, but reclaimed her spot in the lineup for the 2010 Winter Games.
"That four-year span, I was finishing school, I lost my dad, had a significant knee injury," she recalled. "There was so much."
Piper was a late addition to the Olympic team in 2002 when coach Daniele Sauvageau dropped Nancy Drolet from the lineup.
Piper had three goals and two assists in five games in Salt Lake City, Utah. She assisted on the opening goal of the final, which Canada won 3-2.
She's looking for a teaching job in the Toronto area and helping develop players in the Markham Stouffville Stars Girls Hockey Association.
Canadian Olympic team head coach Dan Church was expecting Vaillancourt to continue to the 2014 Olympics.
Injuries and surgeries had kept her out of the lineup for two years prior to the 2013 world championship. The 28-year-old determined her body would not stand up to the rigours of full-time training next winter for the Olympics.
Hockey Canada identifies a pool of national-team players who are eligible for Sport Canada funding of up to $18,000 annually. That funding comes to an end for the trio who just retired.
"There's a very limited retirement transition period," Quinn said. "There's also a special assistance fund they can apply for, which we will help them with, and it's a very limited amount as well."