A review of the literature suggests that good lesson planning sets the stage for good teaching, fostering optimal learning (Skowron, 2015). However, a commonly encountered problem in many educational settings is teachers’ lack of understanding of lesson planning (Ferrer, 2021). Accordingly, this research aimed to investigate Design and Technology teachers’ challenges in developing and implementing lesson plans. The study employed a constructionist epistemology and a mixed-method approach. A sociocultural theoretical perspective underpinned this naturalistic interpretative study. Multiple data collection methods were used, including a questionnaire, interviews, observations, field notes, and secondary documents. The participants involved in this case study were secondary school Design and Technology teachers in Mauritius. Preliminary findings show that the teachers have difficulties understanding the basic principles of lesson planning and implementing lesson plans. The study’s main finding reveals that several teachers do not consider lesson planning important. Findings also indicate that teachers struggle with formulating learning outcomes, using relevant teaching and learning strategies, enacting assessment for learning, and evaluating lessons. In light of the DATTArc-ICTE-TENZ-ITEEA conference 2022, Technology Education: Across the Boundaries, it is argued that professional learning and development in lesson planning is fundamental for teachers to enhance students’ learning in the 21st Century. It is foreseen that this study has important implications for policymakers, teacher-educators, principals and teachers, both locally and internationally.