Brothers Robert and Dean DeLeo and drummer Eric Kretz kicked Weiland out of the band earlier this year (13) and then sued him, claiming he sabotaged the group's recent 20th anniversary tour by turning up late for performances and missing promotional gigs, costing them millions.
Weiland now wants millions from the rockers, claiming they plotted to get him out of the band.
And, in legal documents obtained by Tmz.com, he writes, "How do you expel a man from the band that he started, named, sang lead on every song, wrote the lyrics, and was the face of for twenty years?"
Weiland is also asking that lawmakers formally dissolve the band partnership and he is demanding damages of at least $7 million (£4.5 million).
Stone Temple Pilots have already moved on without Weiland and have recently played two gigs with Linkin Park's Chester Bennington as their frontman.