The 34-year-old is the lead singer of the group Maroon 5 and a judge on NBC's The Voice.
The magazine made the announcement on Tuesday.
Levine is not romantically available. He got engaged to the Namibian Victoria Secret model Behati Prinsloo earlier this year.
In a 2012 interview with The Associated Press, the musician described himself as "nerdy" in high school but admitted he "did OK" with girls.
Levine takes the "sexiest" crown from actor Channing Tatum. He joins the ranks of Bradley Cooper, Ryan Reynolds, Brad Pitt and George Clooney, who all have received the honour.
The annual "sexiest man alive" issue of People magazine hits newsstands on Friday.
Here's 6 super sexy GIFs of Mr Levine in action:
1) Some sexy shades there Adam:
2) We totes agree! We'll never leave the bed!
3) Oh, the sexy ear bite. Yummy!
4) He moves like Jagger!
5) Love the tattoos!
6) Yeah...um...tattoos