This paper proposes an interferometric method of measuring the angular divergence of laser radiation. The method is based on measuring the angular period and counting the number of observed interference orders in reflected light (from a plane-parallel Fabry-Perot etalon). A procedure that uses a precision goniometer (no worse than 1 arc min) is proposed for measuring the angular period of the interference structure. An advantage of the method is that it is simple and highly accurate by comparison with amplitude methods of measurement. A quantitative analysis and the results of certification of the method are presented.