The rapper, whose real name is Johnny Reed McKinzie, was arrested for possession of a firearm in the 13000 block of E. 115th Street in Watts, according to the Los Angeles Police Department.
He was originally stopped for trespassing in the Nickerson Gardens.
LAPD says Jay Rock tried to flee his vehicle when officers wouldn't tell him why he was being detained.
Police also said a firearm was left behind in the vehicle.
He was booked on suspicion of felony weapons violation, police said.
The 39-year-old rapper is known for his work with music label Top Dawg Entertainment and his collaborations with Kendrick Lamar.
In 2019, he won a Grammy award for the song "King's Dead." Later that year, he received the key to his hometown of Watts.