Who is the richest girl in victorious?

It's difficult to definitively say who the "richest" girl in Victorious is because the show doesn't explicitly focus on character wealth. However, there are a few characters who are generally implied to be well-off:

* Tori Vega: While not shown to be exorbitantly wealthy, Tori's family seems comfortable enough to afford her a comfortable lifestyle and even a trip to Hollywood Arts.

* Jade West: Jade is shown to have a good amount of disposable income, enjoys designer clothing, and has access to a luxurious lifestyle.

* Cat Valentine: Cat is shown to be quite wealthy, with her family owning a large mansion and having a private chef.

While it's impossible to say definitively who is the "richest" without concrete evidence, it's likely that Cat Valentine would be considered the wealthiest character based on what's shown in the show.