Tina is one of Joey's sisters.
In "The One With The Boobies", Joey mentions that Tina "can't see her husband anymore, 'cause he got a restraining order". He also states that she is younger than him. When they were younger, Gina and Mary-Theresa convinced Tina that Jelly Beans were diet pills and she gained lots of weight as a result. Later, they convinced her that Jelly Beans were birth control pills, with a similar result. Gina claims that she is the "dumbest Tribbiani". In the Joey episode "Joey and the Fancy Sister", he says that she has a mustache.