Hi Patricia! Welcome to the Disney Parks Moms Panel!
  You are 
visiting the Walt Disney World Resort TOMORROW! Are you giddy like a kid on Christmas morning?! You should be. You are going to have so much fun! 
 I can offer you a big, enthusiastic "yes!" for taking snacks into the theme parks. Not only is it allowed, but I highly recommend it. I often take in familiar snacks for my 
little ones to munch on because no one at the theme parks needs to experience one of them in a "hangry" mood. Taking in snacks to keep their energy up has saved us from many meltdowns! 
 There are a few guidelines you should follow from the 
Park Rules concerning bringing food and beverages with you: no glass containers (except small ones like baby food jars), no alcoholic beverages, and no coolers or backpacks larger than 24" long x 15" wide x 18" high. Since all bags must be checked by security, I try to put my food items in clear containers or bags, so security can more easily see what is in our bags. It helps speed up the process a little to get you in and enjoying the magic a little more quickly! 
 Enjoy your vacation, Patricia! Please let us know if you have any other questions. 
 Tabitha