Thompson was arrested on Friday night after a car he was travelling in was pulled over by police for driving without headlights.
Upon searching the vehicle, police found a duffel bag with a number of small bags containing marijuana, weighing a total of 29 grams.
Thompson was a passenger in the car with two other men, who claimed that the drugs were theirs while Thompson admitted that the bag was his, according to the police report.
The 25-year-old joined the Ravens in 2012 as an undrafted rookie and has since played 13 games in his two seasons, recording 15 career catches for 147 yards and no touchdowns.
He becomes the second member of the Ravens' 2012 Super Bowl-winning team to be arrested in the space of a week after running back Ray Rice was also allegedly involved in an incident with his fiancee in Atlantic City.