This chapter provides a current overview of positive psychology in the workplace. It presents the theoretical foundation and research support for the relevance of positivity in general, and specifically the role positive psychological capital or PsyCap plays in desired employee attitudes, behaviors, and performance. The chapter also provides a summary of the extensive research on the antecedents, development, and outcomes of the POB core construct of PsyCap which consists of the positive psychological resources of Hope, Efficacy, Resilience, and Optimism, or the HERO within. Positive psychology supports ratios of higher positivity over negativity for optimal functioning and "flourishing". Social Cognitive Theory (SCT) posits a reciprocal triangular relationship between the individual, the environment, and behavior. It focuses on five components for agentic processing: symbolizing, forethought, observation, self-regulation, and self-reflection. The reported research on antecedents of PsyCap is relatively less than the extensive empirical evidence on its impact on desired employee attitudes, behaviors, and performance.