This paper examines previous conceptualizations of group solidarity and related concepts in the sociological and social psychological literatures. After identifying ambiguities in previous usages, we define solidarity in terms of relational patterns among actors. Specifically, solidarity is defined in terms of two network properties: the relative directness of ties among actors, and the homogeneity of those ties. In other words, solidarity exists for a given set of actors to the degree that they are directly connected to each other and there is an absence of subgroups or cliques. Although a variety of relational bases are conceivable, we illustrate our new conceptualization in a theory of emotion-based group solidarity. We further develop our formulation to account for the emergence of emotional bonds to the group as a group and the impact of vicarious experiences on emotional processes.