Joey Tribbiani comes from a family of eight children, where he is the only male. He has seven sisters: Gina, Tina, Dina, Mary-Angela, Mary-Therese, Veronica and Cookie. One of Joey's sisters is in prison, however which one it is is unknown.
Tina is one of Joey's younger sisters.
Dina appeared in The One With Monica's Boots where Joey learns that she is pregnant. Dina is Joey's youngest sister. She is considered "the good one" by him. She took the SATs and went to college for "both years", but still isn't terribly bright. At one point, she asks Rachel, "Do you ever worry that you'll be walking and your baby will just slip out?"
When Dina discovered she was pregnant she went to Rachel first, asking her to help her tell Joey. Dina says that Joey is her favorite guy in the world and that she was more scared to tell him that she was pregnant than anyone else.
In the episode The One Where Chandler Can't Remember Which Sister, all seven sisters arrive at Chandler and Joey's apartment for Joey's birthday party. Chandler gets extremely drunk and fools around with one of them, but cannot remembering which sister it was. Chandler eventually finds out it was Mary-Angela, with consequences.
Mary-Angela apparently isn't a talkative person, as her grandmother seems to be used to talking for her, as she answered all of the questions Chandler asked Mary-Angela at the dinner party.
She was portrayed by Holly Gagnier.
Not much is known about Veronica. In the Joey episode, "Joey and the Fancy Sister" he mentions that the way to control her is with food.
Cookie is the most aggressive of the Tribbiani sisters. She is the one that punches Chandler for emotionally hurting her sister when he failed to recognize her after drunkenly sleeping with her in The One Where Chandler Can't Remember Which Sister. She also tells Phoebe that she shot her husband (though she may have been joking just to freak Phoebe out), then made herself a glass of vodka and cranberry juice. In Joey, Joey claims that she has a moustache.
She was portrayed by Alex Meneses.