Abstract The COVID-19 pandemic has disrupted the Bangladesh education system at all levels resulting in the halting of the teaching-learning process in face-to-face contexts. In response, as commonly occurred in other countries, teaching delivery has been shifted online with teachers being the first to react and adapt quickly to this change. This sudden, radical shift in teaching from face-to-face to a distant mode created complexities and challenges for teachers.Centrally, online teaching is inherently different; in this mode, constructivist notions of teaching are implicated. Thus, STEM teachers involved in teacher-centric teaching practices in face-to-face learning found themselves in a pedagogical conundrum as different skills and pedagogical beliefs were required for effective teaching in the online context.Amidst the COVID-19 pandemic, this study attempts to explore STEM teachers’ pedagogical beliefs, understandings, and intentions to teach in the online context. A qualitative methodology has been adopted to examine four STEM teachers’ personal experiences, challenges, beliefs, and practices of online teaching. Purposive sampling has been used to recruit teachers for a semi-structured interview.The findings of this study conceptualize that STEM teachers’ pedagogical beliefs and practices can be viewed as a dynamic, evolving process resulting from the new educational experiences within the online context. They also imply that STEM teachers have individual pedagogical beliefs and strategies pertaining to online teaching which they adapt to construct new knowledge for the delivery of the instruction. The findings of this study help researchers and educators to understand adaptive teaching practice within the notion of constructivist teaching theories. This new body of knowledge might be enlisted to create an effective technology-mediated teaching practice in the current, dynamic educational environment.Keywords: STEM Education, Pedagogical beliefs, Teaching practice, COVID-19, Online Teaching-Learning.