James Oliver Huberty was the perpetrator of the July 18, 1984 McDonald's massacre in San Ysidro, California, USA.

Huberty was veteran of the Vietnam War and worked for 14 years as a welder in Massillon, Ohio. After he lost his job, he moved to California with his wife and children. He worked as a security guard there until he was fired for failing to perform his job properly. One week later, on July 18, 1984, Huberty committed the massacre at the McDonald's restaurant, which was near his apartment. The massacre ended when he was killed by a police sniper.

Victims included Omar Hernandez and David Flores, who were killed first while running for their bicycles. Miguel and Alicia Victoria were the oldest people to die, and Carlos Reyes, an eight-month-old infant, the youngest. Blythe Herrera, Matao Herrera, Victor Rivera, and Gus Vusiluis also died in the attack.

In 1987 Etna Huberty, his widow, unsuccessfully sued McDonald's for USD $5 million, claiming that the massacre was triggered by her husband's consumption of Chicken McNuggets. She alleged that MSG in the food, combined with the high levels of lead and cadmium in Huberty's body, induced delusions and uncontrollable rage. An autopsy did reveal high levels of the metals, most likely built up from fumes inhaled during years of welding.

Mental instability was probably one motive in the shooting. On the day before the massacre, Huberty called a mental health center but his call was not returned, because he had not claimed there was an emergency. Other likely factors include Huberty's heavy drug use and his reported resentment against Mexicans and Mexican Americans, whom he blamed for the loss of his job.