Despite the acknowledged existence of egoism and altruism in human behavior, existing work teams research has primarily employed a descriptive approach to summarizing team behavior that does not distinguish between egoism and altruism. And, despite increasing interest in positive organizational behavior and psychology, much more attention has been paid to understanding team egoistic, compared to altruistic, behavior thus leaving theories of team motivation incomplete. Extending research on team processes and individual level citizenship behavior, we develop a multilevel, dynamic framework that comprehensively establishes the team altruism construct and identifies its key dimensions. We further discuss the unique motives and evolution of team altruism over time. As a result, our theoretical framework: offers a new taxonomy of team altruism, distinguishes team altruism from other related constructs, advances research on team processes by delineating those that are more altruistic from those that are more egoistic, argues that different types of team altruistic behaviors and processes have different antecedents, and generates a number of important directions for future research.