Next year will be Lam's 30th as the Tar Heels' head coach. Lam, who turns 60 on May 18, has a 367-126-4 dual-match record, including a 132-34-1 mark in ACC competition.
"I want to express how grateful I am for the opportunity I have had to coach at this great University," Lam stated in a press release. "When I came here 30 years ago, I intended to stay for one or two years and head back to Big 8 country or a more traditional wrestling community.
"But I fell in love with the University and the people. The administration has taken such good care of me that I never wanted to leave. But it's time. I've done it.
"The commitments to go out recruiting and teaching on the mats each day in the room necessitate a younger person take the program to a higher level. I believe we have a strong foundation in place for that to happen again."
Lam announced his decision to his team Sunday when he called an impromptu team meeting at weightlifting practice, said UNC freshman Chris Rodrigues.
Rodrigues said he wasn't surprised by Lam's announcement.
"When he recruited me, he told me he wouldn't be here for all four of my years," he said. "I heard some things about him waiting for his 30-year pension. And since last year was number 29, it was no surprise to me that he made his decision."
Rodrigues said assistant coach C.D. Mock would be interviewing for the head-coaching job, but that he didn't know if Mock had the inside track to the position.
Lam, who said in the statement that he wanted to announce his retirement a year in advance "so we could make next year a true celebration of Carolina wrestling," led the Tar Heels to five top-10 national finishes.