The couple have two children together.
The singer, 41, tied the knot with motorcycle racer Carey Hart in 2006 and the couple have two children.
Pink, whose real name is Alecia Moore, marked her anniversary on social media, including a playful nod to their occasionally rocky romance.
Alongside pictures of the pair together from throughout their relationship, she said: “15 years. Proud of us babe. See, sometimes being stubborn pays off.
“What a wild ride it’s been, once we learned how to stay in our race line. Here’s to at least the next 15 months hahahAh. I love you and I love our family.”
Pink proposed to Hart in 2005 during a motocross race.
They separated in 2008, two years after walking down the aisle in Costa Rica. They later reunited and welcomed a daughter, Willow Sage, in 2011.
Son Jameson Moon arrived in 2016. Hart, 45, also shared a post to mark the anniversary.
He said: “15 years w/ this amazing woman! Damn, baby!!!!! There is no other woman that I would want to go through this crazy world with than you. Thanks for being a great friend, wife, mother, and person.”