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.
Stockton Police are reexamining their policies for police dogs left in squad cars following the death of a K-9 on Tuesday.
Stockton Metropolitan Airport may begin international flights to Mexico. The proposal could also expand domestic air service.
(AP) - Prosecutors are expected to announce whether they will seek the death penalty against two men charged with killing a bank robbery hostage and two others in Stockton last year.
Stockton Police have increased street patrols in several neighborhoods in Stockton after a wave of gun violence during Memorial Day weekend.
The Stockton City Council has voted to reduce the salaries of the mayor and city council by 30 percent. The discussion about the salary cut during Tuesday night's city council meeting was a heated one.