A window-locking assembly is used on a window assembly and has a body, a drive device and a locking device. The body has a chamber, two detents, a pivot hole, a spring seat and two latch grooves. The drive device is attached pivotally to the body and has a handle, a mounting head and a jacket. The mounting head protrudes from the handle, is mounted rotatably in the pivot hole and extends into the chamber. The locking device is connected to the drive device in the chamber and has a locking arm, a resilient element and a mounting element. The locking arm is attached pivotally to the mounting head with the mounting element. The resilient element is mounted on the spring seat and presses against the locking arm.