Ruby's Diner is a California-based U.S. chain of casual dining restaurants founded in 1982.

The original location was a converted bait shack at the end of the Balboa Pier in Newport Beach.

[1] The first Ruby's Diner opened on December 7, 1982, in a converted bait shop at the end of the Balboa Pier in Newport Beach, California.

On that day, founders Doug Cavanaugh and Ralph Kosmides worked the grill and the cashier station and earned a total of $63.

[2] The restaurant was named after Cavanaugh's mother, and her likeness appears in the logo and other advertising material; a copy of her high school graduation photo is placed next to the register in every location.