<![CDATA[Collaborative learning has established itself as one of the most significant pedagogical approaches in 21st-century primary education. This study presents a systematic review of the development, implementation strategies, and effectiveness of collaborative learning in primary schools, drawing on analysis of 198 Scopus-indexed articles published between 2010 and 2026. Rather than mapping epistemological trends, this review adopts a practice-oriented perspective, examining how collaborative learning works, which strategies have proven effective, under what conditions effectiveness is optimal, and what fundamental implementation challenges exist in real classrooms. Five developmental phases are identified, characterized by successive shifts in focus: from dialogic technology (2010–2014), structuring of cooperative models (2015–2019), redefinition of collaboration in the pandemic era (2020–2022), integration of social-emotional learning and artificial intelligence (2023–2024), and an orientation toward inclusion and educational equity (2025–2026). Strategies such as Jigsaw, STAD, peer tutoring, and collaborative project-based learning consistently demonstrate positive effects on academic achievement (Hedges' g = 0.71–0.79), social-emotional skills, learning motivation, and the formation of long-term social preferences. Critically, this effectiveness is not automatic and is highly dependent on implementation quality, teacher facilitation competence, task design that ensures positive interdependence, and group composition that accounts for cognitive capacity. The most significant challenges identified include the reduction of collaborative learning to procedural group work, weak group process regulation, and unanticipated cognitive heterogeneity. In the Indonesian context, collaborative learning carries strong cultural and policy resonance with the value of gotong royong and the spirit of Kurikulum Merdeka, yet the gap between policy rhetoric and meaningful classroom practice still requires serious attention.]]>
