Purpose: The purpose of this paper is to review social identity theory and its implications for learning in organizations. Design/methodology/approach: This article is a conceptual paper based on a multidisciplinary review of the literature on social identity theory. This article explains the theoretical concepts, constructs, and findings of an identity-based view of learning in organizations. The article describes the theoretical foundations of social identity theory and its elaboration as self-categorization theory, along with some of the limitations of the theory. Important implications for workplace learning are presented. Findings: Although multiple factors influence how people work, social identity theory portends to be a unifying theory of organizational behavior because what and how people think as members of social groups influences subsequent behavior and attitudes in social systems. This influence has important implications for workplace learning. Practical implications: The social identities in organizations serve as important drivers of performance. How people think as members of groups affects the outcomes of learning interventions. Therefore, social identity is a key input to or driver of learning and performance in organizations. Originality/value: Training and development have focused primarily on the individual and occasionally the organizational levels with little attention to the identity-based dynamics of group behavior in organizational settings. This paper offers insights from social identity theory for training and development.