Titled Kamikaze, the Slim Shady rapper, 45, announced its release on Twitter on Thursday.
Along with a link to the music, Eminem, real name Marshall Mathers, wrote: "Tried not 2 overthink this 1... enjoy."
Kamikaze features 13 tracks including a song titled Venom, which is from the upcoming superhero movie starring Tom Hardy.
It has guest appearances from Jessie Reyes, Joyner Lucas, Royce Da 5'9" and Eminem's manager, Paul Rosenberg.
The artwork consists of the tail of a military plane, reminiscent of the cover of the Beastie Boys' 1986 album Licenced to Ill.
The Apple Music album notes said: "Shady punches back, and he's naming names."
Eminem's previous studio album, Revival, was released in 2017. He achieved mainstream popularity with 1999's The Slim Shady LP, which contained the hit My Name Is.
He is not the first artist to release an unexpected album. In June, Beyonce and Jay-Z released a surprise joint LP, titled Everything Is Love.