Girl Group Halloween Costumes

Even though Halloween isn't until Wednesday, it's been a festive few days for people who wanted to get their costumed celebrations in over the weekend. We're loving all the great costume pics being shared on Instagram, Facebook, and Twitter, especially the creative group costumes. If you're planning a "ghouls" night out for Oct. 31, or just need some ideas for a group of female co-workers, be inspired with these girl group costumes from Instagram — including one of our favorites, Nicole Richie and her friends as Troop Beverly Hills!