ABSTRACT Introduction Online interprofessional education is a collaborative process that emphasizes both individual reflection and shared discourses. A useful analytical tool for understanding the complex dynamics of online collaborative learning is the community of inquiry (CoI) framework, which originally held that there are three types of presence in such learning: teaching, cognitive, and social. However, it was later revised to include learning presence, which is characterized by self-regulated learning. Our study aims to refine the construct of learning presence through a clearer understanding of how self- and co-regulation jointly influence learning outcomes. Methods We surveyed 110 people involved with an online interprofessional medical-education curriculum at a university in Hong Kong. Path analysis was adopted to explore the relationships among 1) the three original presences of CoI; 2) learning presence (i.e., for this purpose, a combination of self-regulation and co-regulation); and 3) two learning outcomes: perceived progress and learner satisfaction. Results The results of path analysis indicated that teaching presence had a significant indirect effect, through co-regulation, on perceived progress. In terms of direct relationships, co-regulation significantly and positively influenced both self-regulation and cognitive presence; and social presence had both positive influence on learners’ satisfaction and perceived progress. Discussion This study’s findings suggest the important role of co-regulation in supporting self-regulation, especially in online collaborative-learning environments. Learners’ self-regulation skills are shaped by their social interactions and regulatory activities with others. This further implies that health-professions educators and instructional designers should create learning activities that facilitate the development of co-regulatory skills, as a means of improving learning outcomes. As self-regulation is an important skill for health professions learners’ lifelong learning, and because their future workplaces will be interdisciplinary in nature, it is critical to provide interactive and collaborative learning environments that will promote co-regulation and self-regulation.