A wind turbine gear mechanism with a planetary gear stage arranged on the drive input side and with first and second spur gear stages arranged, in a gear mechanism housing, downstream of the planetary gear stage. The first spur gear stage rotationally and functionally connects a sun gear shaft of the planetary gear stage to an intermediate shaft, the second spur gear stage rotationally and functionally connects the intermediate shaft to a drive output shaft, and only one intermediate shaft is provided. In this case, the gear mechanism housing has a separation joint along which the gear mechanism housing can be divided into a main housing portion and a housing cover in such manner that a separation joint plane passes through the central axis of the intermediate shaft and the separation joint plane extends a distance away from the central axis of the sun gear shaft.