Ker v. California, 374 U.S. 23 (1963), was a case before the United States Supreme Court, which incorporated the Fourth Amendment's protections against illegal search and seizure.

The two were arrested after officers from the Los Angeles County Sheriff's Department saw George Ker meeting another person who was suspected of selling illegal drugs.

After losing their prime suspect, the officers went to the Kers' apartment and entered without consent or a warrant using a pass key supplied by the building manager.

Clark's opinion addressed “the specific question as to whether Mapp requires the exclusion of evidence in this case which the California District Court of Appeal has held to be lawfully seized.” Unlike the previous case, where the search was clearly unreasonable, the District Court had found that the seizure of the drugs in the Kers’ apartment was allowed as being incident to an otherwise lawful arrest.

Ker has been cited by subsequent decisions both for the holding of Fourth Amendment incorporation and for allowing warrantless search and seizure with probable cause or to prevent destruction of contraband.