The invention relates to a method of generating frequency-tripled laser radiation (THG). It is the object of the invention to demonstrate an efficient approach to generating frequency-tripled laser radiation. The method according to the invention comprises the following method steps: providing a first laser radiation at a fundamental frequency, coupling the first laser radiation into an optical resonator, which is resonant at the fundamental frequency, generating a second laser radiation by second-harmonic generation of the first laser radiation in a type-I process in a first nonlinear optical crystal (3), which is located in the optical resonator, wherein the second laser radiation has a polarization direction, rotating the polarization direction of the second laser radiation, preferably by an angle of substantially 90°, and generating a third laser radiation by generating the sum frequency of the first and second laser radiations in a type-I process in a second nonlinear optical crystal (9), which is likewise located in the optical resonator. The invention also relates to a device for generating frequency-tripled laser radiation.