A lead screw window operator (100) utilizes a lead screw (110) that is in tension whether the operator is being used to open or close a window assembly (10). The lead screw window operator (100) may include a nut (170) that has edges sufficiently close to first and second support surfaces to prevent excess rotation of the nut (170). Also, the lead screw (110) may have a splined end to operatively connect to a first gear that has a splined profile to allow the gear to slide along the lead screw along a longitudinal axis.