Structured inquiry-based learning assisted by a virtual laboratory is necessary for senior high students to help their conceptual understanding of wave optics. Experimental mixed-method design with one group pretest-posttest model used for physics class. Data collected from an interview, observation, pretest, and posttest in quantitative and qualitative data. The result is structured inquiry-based learning assisted by virtual laboratory effective improving students' conceptual mastery of wave optics. Furthermore, it also has been found that students still have some difficulties with interference and diffraction after learning.