Increasing demands for optical anticounterfeiting technology require the development of versatile luminescent materials with tunable photoluminescence properties. Herein, a number of fluorescent carbon‐ and oxygen‐doped hexagonal boron nitride (denoted as BCNO) phosphors are found to offer a such high‐tech anticounterfeiting solution. These multicolor BCNO powders, developed in a two‐step process with controlled annealing and oxidation, feature rod‐like particle shape, with varied luminescence properties. Studies of the optical properties of BCNO, along with other characterization, provide insight into this underexplored material. Anticounterfeiting applications are demonstrated with printed patterns which are indistinguishable to the naked eye under visible light but become highly discernible under UV irradiation. The fabricated patterns are demonstrated to be both chemically stable in corrosive environments and physically robust in mechanical bending testing. These properties render BCNO as promising and versatile anticounterfeiting material a wide variety of environments.