The plaintiffs say the "shelter has a duty to help, not harm, homeless dogs and cats."
The Animal Legal Defense Fund along with three people from Stockton filed the lawsuit against the City of Stockton.
The suit is not asking for money, only that the animal shelter follow the law.
The shelter is required to hold strays for at least 6 days before euthanization.
But Animal Legal Defense Fund Attorney Jenni James says the shelter's records show a different story over a one year period.
"Early euthansias are happening, 1,500 animals were euthanized before the expiration of the Stockton shelter's minimum holding period," says James.
James says 80 percent of the animals are behind locked doors where the public never sees them.
"Only about 20 percent of the animals are truly being given a meaningful chance of adoption," says James.
The City of Stockton is not commenting on the lawsuit.
Police say the hostage who died during a Stockton bank robbery and shootout was killed by police, not the suspects.
(AP) -- Authorities announced a reward of $50,000 for information that leads to the arrest of a fourth suspect in the deadly shootout in Stockton.
The annual asparagus festival in Stockton called it quits after 29 years. But it will return next year with a new name and a new location for its 30th incarnation.
(AP) -- The surviving suspect in a bank robbery that ended in a deadly shootout has been charged
(AP) -- A Stockton robbery suspect is expected to be charged Monday with the deaths of a woman taken hostage and two other robbery suspects