The systematic review in this study focuses on questionnaire-based quantitative and qualitative studies that focus on the role of massive open online courses (MOOCs) in teacher professional development, with a concentration on the COVID-19 lockdown period. Sixteen studies were selected to be included in this systematic review based on the inclusion and exclusion criteria. The study was designed to answer four main questions: (a) how have MOOCs been used in teacher professional development during the COVID-19 crisis? (b) what are teachers' perspectives toward using MOOCs for professional development? (c) what teacher skills reported as critical in those studies can be improved using MOOCs? and (d) what challenges faced by teachers during the use of MOOCs for training are reported in those studies? The results of this review reveal that (i) MOOCs were used to support teachers moving online, improve their personal skills during that crisis, and allow them to meet teachers in different areas and share their experience through online camps; (ii) teachers viewed a set of positive and negative aspects of the available MOOCs, and they addressed some criticisms of the available MOOCs and factors that may impact the success of MOOCs; (iii) MOOCs during the COVID-19 pandemic focused on developing three types of skills in teachers: online teaching skills, personal skills, and specialization skills; and (iv) financial and technical challenges, the quality of the available MOOC content, and the lack of time combined with their duties during that time are the most critical challenges teacher faced.