okay so uh i was looking up how old mable and diper are it said there both 13 and i come alone someone asking what grade are mable and dipper in and when i check the answer: What grade is Dipper and Mabel in? 2nd grade Dipper and Mabel are in 2nd grade. Timeline | Gravity Falls Wiki | Fandomgravityfalls.fandom.com › wiki › Timeline Search for: What grade is Dipper and Mabel in?