The chapter starts with some recommendations for the selection of the landing gear arrangement for an aircraft (including the number of wheels and gears), discusses in detail the geometric parameters and performance of aircraft with a taildragger, tricycle, tandem landing gear with outriggers, and a multiple-wheel landing gear. The chapter shows how to estimate aircraft ground roll maneuverability, as well as how to design structural and kinematic diagrams of the retractable landing gear. At the end of the chapter, the reader will learn about possible design solutions to reduce the volume of the landing gear in the retracted position.