The purpose of this study is to probe the main determinants of organizational trust, as identified in the relevant literature: cognition-based (i.e., rational) trust and affect-based (i.e., relational) trust. This study explores the nature of trust among public employees and identifies important antecedents and moderating conditions based on systematic and rigorous empirical research. Using large data sets from Merit Principles Survey (MPS) and Best Places to Work (BPTW), as well as drawing upon the scholarly works from several disciplines, this study develops an antecedent-trust model and analyzes the different types of antecedents of organizational trust in the public sector at a hierarchical and multilevel ordering structure. The focus of the study is empirically testing the effects of vertical and shared leadership behaviors and work motivation attributes on organizational trust within U.S. federal agencies. In addition, the moderating impact of leadership on the relationship between work motivation and organizational trust is examined. This research finds that some of these predictors and moderators (e.g., vertical and shared leadership behaviors) play significant roles in fostering organizational trust directly and indirectly. Based on a discussion of the main findings, research and practical implications for public management theory and practice are provided.