Deontay Wilder spent part of his Tuesday morning locked behind bars ... TMZ Sports has learned the star boxer was arrested in Los Angeles following a routine traffic stop.

Law enforcement sources tell us ... Wilder was pulled over in Hollywood at around 1:15 AM after LAPD officers claimed his Rolls-Royce's windows were illegally tinted and his license plate was obstructed.

During the stop, cops say they smelled an odor of burnt marijuana coming from his ride -- so they searched the car. Our sources say they then found weed and a 9mm in the vehicle, and put Wilder into custody. We're told the 6-foot-7 fighter was cooperative and nice throughout the whole ordeal.

Our sources say the 37-year-old was booked on a charge of possession of a concealed weapon. Jail records show he bonded out at 6:34 AM.

Wilder -- a 43-2-1 fighter with 42 knockouts on his resume -- has been rumored to be the next opponent for Anthony Joshua ... with the heavyweight superfight expected to go down at some point in 2023.

It's unclear if Tuesday's arrest will have any impact on the fight's negotiations.