As mentioned before, Disney Resorts offer guests Extra Magic Hours so they can get to certain parks early, or stay late, to enjoy select attractions. Anyone staying at official resort hotels, Walt Disney World Swan Hotel, Walt Disney World Dolphin Hotel, and Shades of Green Resort can get in on the fun (just check with the receptionist for the full schedule upon arrival).
Bonus tip: In addition to Extra Magic Hours, parks may stay open late for seasonal events. Make sure you check the Disney World website (the blog is also a great resource) ahead of your trip, or talk to someone in guest services, so you know when to purchase tickets.