Lawyer Alan Gold said in an email that authorities "agreed with us that there was no reasonable prospect of conviction."
Valanciunas was arrested in April in Wasaga Beach, Ontario, before the Raptors started a first-round playoff series against the Brooklyn Nets.
Police had followed up on a report that a vehicle went through a drive-thru with open beer bottles visible. Police say officers located the vehicle at a home, where they arrested Valanciunas.
Valanciunas did not miss any playoff games. He averaged 10.9 points and 9.7 rebounds in seven games against the Nets.