Abstract
This paper focuses on comparing collaborative group sizes (small versus large) in terms of developing preservice teachers' skills in designing webpages using HTML in a project-based learning environment. It examines the effect that group size has on academic achievement and product quality in project-based learning environments. The experiment involved 74 undergraduate students enrolled in the sixth level of the Computer Teacher Program, Faculty of Education, King Faisal University in Saudi Arabia, during the second term of the school year 2018-2019. Study results indicate that there are significant differences between large and small size groups as they relate to students' academic achievement and product quality, showing a preference for a large group, which disagrees with most of the existing literature. In this study, the researchers explain this disagreement and recommend new directions in researching group sizes in project-based learning environments in the future.