Hello Amber! Welcome to the Disney Parks Moms Panel.
My daughter never seems to grow. She is also squeamish about any ride that moves faster than Dumbo The Flying Elephant, so the height requirements for certain rides at Walt Disney World Resort have not become an issue yet. As my younger son grows, we are about to have concerns about having to tell him he just isn't tall enough for certain attractions.
The range for height requirement on certain attractions is 35" (The Barnstormer in Magic Kingdom) to 48" (Rock 'n' Roller Coaster at Disney's Hollywood Studios). If your child falls between that range, then being prepared is your best bet toward avoiding disappointed Mouseketeers.
The
Disney Parks Blog released a wonderful series of diagrams outlining the height requirements for all of the attractions at Walt Disney World Theme Parks in 2015. If you use these, double check that none of the height requirements have changed since that information became available (it looks the same to me) and look for the height requirements for any attractions that have been added since that time.
The height requirements are also listed for each attraction on the Park Maps.
When I plan for my little ones, I focus on what they can do more than what they cannot by looking at the
planning guides for preschoolers including the list of
attractions that are great for preschoolers.
As far as being checked for height, Cast Members at the attractions are required to check your child's height at any attraction with a height requirement if they believe your little one is not tall enough to ride.
Stand Tall!
~Todd