This study aims to investigate the perspectives of primary school teachers in South Africa, who participated in a "Lesson Study" (LS) project, on this professional development process and about their professional learning. The study followed a mixed approach, with data collected through a questionnaire, followed up by interviews. A novel approach in this study was to source teachers' experiences of the individual stages of LS as well as of the integrated process. Teachers' perspectives on LS were categorised into 5 themes: "collaboration -- commitment and the free rider effect," "confidence issues," "teachers' knowledge and skills," "misconceptions about the LS approach," and "external issues including concerns over time of teachers and learners, systemic challenges and school management." Using teachers' individual and focus group inputs in the questionnaire and the interviews, we report about their experiences.