Collaborative learning, a classroom structure wherein students work with peers to co-construct knowledge, can lead to higher achievement and more equitable opportunities to learn in comparison to traditional instruction. However, there is much to learn regarding the conditions by which collaboration supports positive outcomes. In this dissertation, I contribute to the growing body of research determining the conditions of collaborative learning by examining (a) how researchers analyze discourse in the context of mathematical group problem-solving, (b) how middle grade students develop learning opportunities through conflict, and (c) how middle grade students collectively engage to solve complex tasks. The first article is a systematic review illustrating how scholars analyze discourse in the context of mathematical group problem-solving. I synthesized literature according to six categories: affective experiences, group coordination, individual or group success, collective understanding, language and content, and interventions or specific content. Article 1 provided an analytic basis for the empirical analyses. For Article 2 and Article 3, 77 middle grade students across two schools were placed into groups to work collaboratively on complex mathematical tasks. In Article 2, I examined instances of group conflict to determine how learners resolved conflict in ways that promoted or inhibited learning opportunities. I constructed 17 themes of promotive discourse practices and six themes of limiting discourse practices. These themes suggest implications for teaching students how to communicate in collaborative environments. In Article 3, I constructed a theoretical frame for determining how middle grade groups collectively engage to solve complex tasks. I theorized that students’ intellectual positionings intersected their individual engagement to inform collective engagement structures. I also categorized the collective engagement structures exhibited by the middle grade sample. These structures included: Follow The Leader, Do What I Say, Let’s Compete, Let’s Work Hard And Figure This Out, We’re Really Into This, Let’s Have Fun, Let’s Get The Job Done, and Every Person For Themselves. The theoretical and empirical contributions of Article 3 inform researchers and practitioners towards understanding the collaborative processes that result from collaborative learning. Together, this three-article dissertation creates stimulus for discussion and future inquiry towards improving collaborative approaches to instruction.