There is a growing interest in conceptualizing, defining, and assessing what are often called 21st century skills or deeper learning competencies. The purpose of this literature review is to explore the conceptualizations, definitions, and understandings in the research literature related to collaboration. Key initial questions include: What is collaboration? How is collaboration related to other success skill concepts? And to what extent does collaboration develop over time? This foundational information will then be used to examine (a) instructional approaches to promote collaboration, (b) benefits of collaboration on valued student outcomes such as student learning, and (c) ways teachers can collect evidence that reveals the benefits of student collaborative outcomes using student artifacts and other appropriate measures.