The Clanwilliam clubman, who has been named in the province's squad to face the Scarlets, has played 210 competitive games for Munster since making his debut in November 1996.
He was capped 27 times for Ireland at Test level, with his six-try haul including touchdowns against Namibia and Argentina at the 2003 Rugby World Cup.
Quinlan has been part of all of Munster's successes in the modern era - their Celtic League, Celtic Cup and Magners League triumphs and both of their Heineken Cup wins.
In the 2005/06 campaign, he suffered an injury in the Heineken Cup pool opener against Sale Sharks that kept him out for most of the season, recovering in time to help Munster secure their inaugural Heineken Cup title.
Commenting on today's news, head coach Tony McGahan said: "Alan Quinlan has been an integral part of the success of Munster Rugby for the past 15 years.
"His longevity in what is a highly attritional profession is a tribute to his dedication, application and durability.
"Alan was a player's player whose impact in big games and ability to turn a negative situation into a positive action made him a great player to have on your side and a crowd favourite."
He added: "His decision to call it a day at the end of this season of course evokes a sense of poignancy for all of us who have worked with him.
"But it's balanced by the knowledge that he can look back on a great career with pride at what he's achieved. He leaves us with our thanks and very best wishes for the future."