A magnetic lock which requires only a single magnet for operation, yet which is biased into a locking position. A latch is slideably mounted in a slide way defined by a housing with a latch opening at one end. The latch comprises a magnet at its base, and a latch positioner of ferromagnetic material is positioned within the housing alongside the latch. The positioner is longer than the magnet, such that the magnetic field biases the magnet to locate at the center of the length of the latch positioner. The latch itself is sufficiently long that it projects beyond the latch opening of the housing when the magnet is allowed to center. The slide way is open below the magnet a sufficient distance that when a “key” of a ferromagnetic, or optionally magnetic, material, is located near the base of the housing, the magnet and its associated latch are drawn further into the housing a sufficient distance that the latch is drawn out of the way of an associated catch.