An adjustable seat assembly for a motorcycle includes a seat pan with a first portion and a second portion, and an adjustment mechanism. The first portion of the seat pan has a fastening portion for the non-adjustable fastening of the first portion on the motorcycle, preferably on a tank of the motorcycle. The adjustment mechanism is connected to the second portion of the seat pan and is configured to adjust the height and/or inclination of the second portion of the seat pan in relation to the first portion. A motorcycle with the adjustable seat assembly is also provided.