One of the best throwbacks of the bunch was by Nicole Crimi, the actress who played Regina Geoge's belly dancing little sister, Kylie.
"On October 3rd he asked me what day it was... "It's October 3rd." #nationalmeangirlsday 💋," the child star wrote on Instagram, alongside a photo of her movie (cool) mum.
"Ps. You should check out her boob job, they're hard as rocks!! 😉" she joked.
While we may remember her with Kelis' 'Milkshake' song playing, Nicole is now all grown up. According to IMDB, she hasn't acted since 2006, instead the 21-year-old is about to finish university.
Aside from reintroducing us to Nicole, this year was extra special with the Mean Girls cast, including Lindsay Lohan and Amanda Seyfried, coming together to support the victims of the Las Vegas shooting.