Abstract: A sliding-type window frame includes a jamb frame assembly having a top jamb member, a bottom jamb member spaced apart from the top jamb member in a longitudinal direction, and left and right upright side jamb members spaced apart from each other in a transverse direction and interconnected to the top and bottom jamb members. The top jamb member has a top channel body that confines a space for receiving a top end of a window panel and that has two opposite ends connected to the side jamb members respectively, and a sash plate that extends between the side jamb members and that is mounted movably in the top channel body so as to be movable in the space between lower and upper positions. The sash plate has a lower surface formed with at least one track member to engage the top end of the window panel when the sash plate is at the lower position.