Double plasma resonance occurs when the upper hybrid frequency coincides with one of the cyclotron harmonic frequencies in a magnetized plasma. This gives rise to a sharp intensification of the plasma wave instability. The radiation mechanism based on this effect allows one to explain the origin of the "zebra pattern" in radio spectra of the Sun, Jupiter and the Crab pulsar. Successful interpretation of spectra of diverse astronomical objects in terms of the double plasma resonance effect points to the universal character of this phenomenon under a broad range of astrophysical conditions.