Hi Sage!
The
Walt Disney World website has an excellent guide for height restrictions on attractions. You can sort by park, height, recommended ages and more.
There are many attractions that don't have a height requirement at all. Attractions such as it's a small world, Buzz Lightyear's Space Ranger Spin, Astro Orbitor, Winnie the Pooh and Dumbo are great for children and adults of all ages. There are also many shows with no movement at all that are entertaining for kids of all ages, such as Mickey's PhilharMagic and Country Bear Jamboree.
Other attractions have a height requirement, which can range from 32 to 52 inches. Check out the
height restrictions guide to find the attractions for your 3 year-old's height.
When you visit, make sure to take your little one to Fantasyland at Magic Kingdom and Hollywood Studios. Those parks have excellent attractions for toddlers!
I hope you have a magical vacation!
Magically,
Stacy