RollerCoaster Tycoon 3 is a construction and management simulation computer game. It is the third installment in the RollerCoaster Tycoon series, first released on October 26, 2004 in North America. RollerCoaster Tycoon 3 places players in charge of managing amusement parks; rides can be built or demolished, terrain and scenery can be adjusted, and prices can be controlled to keep visitors or "peeps" happy.

RollerCoaster Tycoon 3 features two methods of gameplay. In career mode, players must complete predetermined objectives in predesigned scenarios. In the new sandbox mode, players have unlimited time and money to create their own custom parks. New features include the ability to import and export custom attractions, design custom scenarios and peeps, as well as design an in-game recorder and a fully three dimensional world players can view from all angles. In May 2012, a portable sequel, RollerCoaster Tycoon 3D, will be released.

Like the previous games in the series, RollerCoaster Tycoon 3 is a strategy and simulation game in which players manage all aspects of an amusement park by building or removing rides, scenery and amenities, adjusting the park's finances, hiring staff, and keeping the park visitors, known as "peeps", happy. RollerCoaster Tycoon 3 features two main game modes. The career mode features scenarios where players must accomplish goals, such as impressing a visiting celebrity or attaining a certain park rating. Each scenario has three levels of objectives, which are ranked as Apprentice, Entrepreneur, and Tycoon; the higher the level, the more challenging the goal is to complete. A third of the scenarios are playable from the start, with the rest unlocked when the player completes the objectives at each level. The second mode of play is the sandbox mode. Players are given a large, empty plot of land and unlimited funds with which to build their own custom and dream parks.

RollerCoaster Tycoon is a construction and management simulation video game that simulates amusement park management. Developed by MicroProse and Chris Sawyer and published by Hasbro Interactive, the game was released for Microsoft Windows on March 31, 1999 and was later ported to the Xbox game console. It is the first game in the RollerCoaster Tycoon series and is followed by RollerCoaster Tycoon 2, RollerCoaster Tycoon 3, and the upcoming RollerCoaster Tycoon 3D.

RollerCoaster Tycoon itself has received two expansion packs: Added Attractions (released in the US as Corkscrew Follies) in 1999, and Loopy Landscapes in 2000. Two special editions were released: RollerCoaster Tycoon Gold/Totally RollerCoaster in 2002, which contained the original game and Corkscrew Follies; and Roller Coaster Tycoon Deluxe in 2003, which contained the content in Gold plus Loopy Landscapes.

Chris Sawyer originally wanted to create a sequel to his highly successful Transport Tycoon, but after becoming obsessed with roller coasters, he changed the project into RollerCoaster Tycoon. Sawyer wrote RollerCoaster Tycoon almost entirely in assembly language, a difficult process given the game's complexity. Some functions were written in C to interface with the Windows operating system.