Concealable stigmatized identities (CSIs) are devalued social identities or attributes, such as mental illness, HIV+ status, and chronic illness, that can be kept concealed from others. We describe two components of a CSI—valenced content and magnitude—that we argue are critical in determining the impact of a CSI on psychological, physical, and behavioral health outcomes. Valenced content contains a range of both negative and positive beliefs about the CSI, including internalized stigma, experienced discrimination, anticipated stigma, disclosure reactions, and counterstereotypic/positive information. Magnitude of the identity captures the relative importance of the identity for the self via measures of centrality and salience. A review of the research literature finds initial support for the importance of valenced content and magnitude impacting psychological, physical, and behavioral outcomes, although many relationships are yet to be rigorously tested. We include a set of suggested policy implications aimed at reducing stigma among people with CSIs and, thereby, improving health.