Rimantas Grigas (born 1962) is a Lithuanian basketball coach, currently signed with Žalgiris Kaunas.Grigas is currently the head coach for Zalrigis, replacing recently let go Aco Petrović.
He was coaching Atletas Kaunas in the 1996-1999 season. Before entering Žalgiris Kaunas coach staff, he was signed with Žalgiris stand-in. Furhermore, before the resignation of previous headcoach Ainars Bagatskis, he was his assistant.
First his win with BC Žalgiris was Lithuanian Basketball Federation Cup, was won on 2007 February 7. In 2007 May 22 team has won Lithuanian Basketball League Gold medals.