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 complex communication. Key initial questions include: What is complex communication? How is complex communication related to other success skill concepts? And to what extent does complex communication develop over time? This foundational information will then be used to examine: (1) instructional approaches to promote complex communication; (2) benefits of complex communication on valued student outcomes such as student learning; and (3) ways teachers can collect evidence that reveals the benefits of complex communication using student artifacts and other appropriate measures.