A generalized three-dimensional line-of-Sight guidance with lead angle (GLOS) is presented for maneuvering targets. In the proposed guidance law, we define a desired line-of-Sight (LOS) from the tracker by taking the target future maneuvers into account. Because of the limitation of the tracker field-of-view (FOV), the lead angles in the azimuth and elevation channels must be fractions of the azimuth and elevation angles for straight collision trajectory. Simulation results show that GLOS has better performance, i.e., lower miss distance and total control effort, than the conventional LOS guidance with lead angle.