The overall aim of this research was to examine the effectiveness of puzzle-based learning approach on secondary school students' attitudes and their self-efficacy beliefs in English lesson. The research employed the mixed model and quasi-experimental design with pre-test/post-test was applied. The working group was consisted of the 8th grade students who were selected from two classes and who learned at Elbistan Secondary School during the 2017-2018 academic year. The study was conducted with two groups; experimental group and control group. While lessons were taught based on puzzle-based learning approach in experimental group, in control group the lessons were taught according to the suggested methods of English lesson curriculum. At the end of the study, experimental group students' attitudes and self-efficacy beliefs in English lesson scores increased within groups and between groups. The activities which were carried out in the context of puzzle-based learning were considered as effective applications by students. Observations done during the implementation process of puzzle-based learning in experimental group revealed that the students had fun and learned, and their active participation increased during lessons.