The Forget You singer was accused of putting the drug into the woman's drink while they were at a downtown Los Angeles restaurant.
The woman said she had one drink with Green, whose real name is Thomas DeCarlo Calloway, and then woke up naked with him the next morning. She said she had no further recollection of the previous night.
Green pleaded no contest to the charges Friday and was sentenced to three years of formal probation, 360 hours of community service and 52 Alcoholics Anonymous or Narcotics Anonymous meetings.
He was ordered to return to court in March for a progress reported.
No sex-related charges were filed against Green in relation to his interaction to the woman.