Photoelectric observations of SW Lacertae, an eclipsing binary of the W Ursae Majoris type, were made in three colors-yellow, blue, and ultraviolet-in 1953 and in yellow and blue in 1954, all on the U, B, system. Comparison shows that, while the system was "well behaved" in 1953, it was quite erratic in 1954, varying from observation to observation as well as from cycle to cycle, and was about 0.09 mag. bluer in color. The light-curves are asymmetric and have deformations which prevent normal rectification, giving a family of solutions. When the spectroscopic and the approximate photometric elements are combined, they show the more massive star to be eclipsed at secondary minimum-an occultation. Times of minima show the period to be steadily increasing.