"Glover is one of our team leaders, and throughout his career has been a consummate professional on and off the field," Lions general manager Bob Quinn said in a statement. "We are thrilled that he will be a Lion for the next three seasons. I also want to thank Glover and his representatives for their work in making this contract extension a reality."
Quin, 31, has spent the last four seasons with the Lions. He recorded 68 tackles and two interceptions in 2016.
One of Detroit's most consistent defensive playmakers, Quin led the NFL in interceptions, made the Pro Bowl and was named a second-team All-Pro in 2014. While he hasn't matched those heights in subsequent years, Quin is a stalwart whose name almost never shows up on the injury report.
Quin's 116 consecutive regular-season starts are the most among NFL safeties. He has only missed one game in his NFL career, which came during his rookie season with the Houston Texans.
"My body feels good, actually," Quin said this offseason, per Kyle Meinke of MLive.com. "I feel like I'm 25 again. Like, I actually feel better now than I felt last year. When the season was over with, I had a birthday, and I turned 31, and my wife was like, 'Hey now, you know the older you get, you can't take that off time like you used to take. It's a little harder to get the weight off and get in shape.'"
Pro Football Focus ranked Quin 27th among all safeties last season. He earned his strongest marks in coverage.
ESPN's Adam Schefter reported the deal is worth $13 million ($9.5 million guaranteed) for the additional two seasons. He was previously set to become an unrestricted free agent after the 2017 campaign.