Griner, 31, admitted possessing cannabis oil but told the court she made an "honest mistake".
But the court convicted her of smuggling and possessing narcotics, and gave her close to the maximum sentence recommended by prosecutors.
Griner is a double Olympic gold medallist and is considered one of the best players in the world.
She was detained in February at an airport near Moscow when vape cartridges containing cannabis oil were found in her luggage. She had come to Russia to play club basketball during the US off-season.