60 Diner is a chain of small restaurants in Liberty City. These places are inaccessible to the player. However, the player can take a friend or girlfriend on a date there. These diners are a good choice of eating venue when on dates with Kate McReary. The name is a pun of "69-er" (sixty niner), which in turn refers to the 69 sex position.
The exterior of the 60 Diner in Westminster looks similar to The 69th Street Diner in Hove Beach, Broker. There is a door at the front and a sign above it that says "60 Diner". Its shape is a lot like a giant trailer from the outside.