The shooting happened in Woodville just before 8:30 on Saturday night.
The sheriff's office believes 31-year-old Ruben Sanchez shot 30-year-old Rachel Martinez after an argument.
When deputies arrived, they found Martinez dead at the scene.
Detectives are looking for Sanchez, who previously lived in Oregon and Washington and might try to go back. They believe he is still armed with the gun he used to kill Sanchez.
Anyone with information is urged to contact Detective J. Melendez or Sgt. B. Clower at the Tulare County Sheriff's Office at 559-733-6218 or 559-802-9563.