The design procedure of a uniaxial anisotropic equilateral triangular dielectric resonator antenna (ETDRA) is presented for the first time. The uniaxial material is realized by a periodic stack of sheets of two dissimilar materials with different dielectric constants. It is proven that the increase of the boresight gain and impedance bandwidth of the ETDRA is possible by using the uniaxial material for the antenna prism. The gain improvement is due to the increase in the sidewall radiations and the bandwidth enhancement is owing to the lowering of the effective permittivity of the structure. The fabricated anisotropic ETDRA offers an impedance bandwidth of 27.7% between 3.025 and 4 GHz with a measured gain above 8 dB. The simulation results agree well with the experimental ones.