Christian Slater's wife Ryan Haddon will not be charged after she allegedly hit the actor on the head with a drinking glass.
Clark County District Attorney David Roger launched an investigation after Slater was injured in an incident at a hotel in Las Vegas on 10 November.
Slater received nine stitches for a cut behind his ear while Haddon spent several hours at the county jail.
The couple told police that it was an accident.
Roger said that the investigation could not prove beyond a reasonable doubt that Haddon had intended to injure her husband.