Optimizing collaborative behavior is crucial in educational activities, directly improving academic performance, social skills, and social-emotional learning for both teachers and students. In an effort to decipher the mechanisms underlying the effectiveness of collaborative learning, educators and neuroscientists have initiated the collection and analysis of learners’ physiological parameters during such collaborative exercises. Considering both accuracy and portability, functional near-infrared spectroscopy (fNIRS) has emerged as a viable tool. The current study aims to understand its potential for studying neural mechanisms of collaboration. Sixty articles were reviewed from three databases to address three research questions: (1) What are the characteristics (i.e., number of publications per year and for different age groups of participants, sample size, and the usage of fNIRS devices) of fNIRS-based collaboration research? (2) What experimental designs are commonly employed in fNIRS-based collaboration research? (3) What is the relationship between neural activity and interactive behavioral performance? The results provide a comprehensive descriptive statistical analysis of the literature characteristics and offer a detailed summary of the research methods employed, including the experimental protocol, task, and duration. Importantly, these findings demonstrate compelling evidence of inter-brain synchrony (IBS), indicating synchronized cortical activities between interacting individuals, and it was observed in the prefrontal cortex or temporoparietal cortex during collaboration and interaction tasks, highlighting the crucial role of these brain regions in facilitating collaborative behavior. The finding of this review advanced our understanding of how fNIRS is ultilized in collaborative research and offer practical implications for designing educational interventions or programs aimd at enhancing collaborative behaviors and their associated benefits.