One of the more complex areas of physics is wave optics. By conducting various researches, certain student difficulties in understanding the concepts of wave optics have been identified. Understanding student difficulties is the key to designing a quality teaching sequence that would induce students’ intellectual engagement and develop an understanding of basic wave concepts. A new teaching sequence was designed for research-oriented teaching of wave optics lasting 8 teaching hours. Teaching materials were tested in a general gymnasium in Zagreb. The research was conducted in the form of semi-structured interviews that were audio-recorded, transcribed, and qualitatively analyzed. The aim was to assess students’ understanding of the basic concepts of wave optics, to identify students’ difficulties, and to assess the effectiveness of the designed teaching sequence. The student difficulties that arose during the research are presented, individual student answers are highlighted and analyzed, and the implications for research-oriented teaching of physics are given. This thesis is designed as a contribution to the qualitative evaluation of the effect of a new teaching sequence in wave optics. It can also serve as an example to teachers of the researched teaching of wave optics as this teaching approach has proven to be useful and effective