Research on social identification in organizations is diverse and evolving. As focus has shifted to the effects of multiple identities, there is a need to further define relationships between the three primary work identification targets (i.e., team, organization, and profession) and outcomes, specifically as to how each identification target explains variance in outcomes simultaneously. We meta-analytically test the relationship between each identification target and fifteen attitudes, three behaviors, and five general well-being variables at work with 483 studies and 557 independent samples (N = 179,442). We then provide evidence for the relative importance of each identification target through meta-analytic relative weights and regression analysis. Categorizing attitudes according to the same level (team, organization, profession), we found that organizational and team identification were most important in predicting matching attitudes, in support of the identity-matching principle. For professional-focused attitudes, behaviors, and general well-being, results were less clear; each identity target explained a range of variance in outcomes. There was a trend of team identification being the most important predictor, particularly for well-being. Through meta-analytic structural equation modeling (MASEM), we tested the self-esteem hypothesis from social identity theory; results show that effects from identification to outcomes transmitted through self-esteem were weaker than direct effects.