This quantitative review systematically integrates the antecedents and outcomes of psychological ownership (PO) and examines its incremental validity and explanatory power compared with two other forms of workplace attachment (i.e., organizational commitment and organizational identification). Across 141 studies published over 20 years, our meta-analysis shows that apart from the factors related to the three traditional categories of PO antecedents (i.e., control, knowing, and investment), safety (e.g., organizational justice, trust, perceived organizational support, and relational closeness) is an emerging antecedent leading to PO. In addition, we find that PO is related not only to employees’ attitudinal and performance outcomes but also to some dark-side outcomes (e.g., territorial behaviors). Furthermore, after applying two advanced methods, that is, two-stage meta-analytic structural equation modeling and dominance analysis, to the analysis of 294 studies (including 291 primary studies and three published meta-analyses), the results reveal that PO has an incremental validity above that of organizational commitment and organizational identification in predicting employees’ in-role performance and organizational citizenship behaviors. Theoretical and practical implications are discussed.