In today's global competitive environment, many organizations utilize virtual workgroups to overcome geographic and organizational boundaries. Research into their dynamics has received the attention of scholars within multiple disciplines, and the potential for an integrative approach to the study of virtual workgroups exists. This dissertation is a first step towards such an approach. The primary aim of this research is to examine antecedent and contextual factors that affect the emergence and effectiveness of leaders in virtual workgroups. To achieve this aim, an integrative model assembled from theory and empirical findings in leadership, management, social identity, and communications research is posited. Hypothesized relationships depicted in the model identify key dispositional and contextual variables linked to leader emergence, member behavior, and leader effectiveness within virtual workgroups. This study employed a nonexperimental research design, in which leader emergence and social identity manifest as naturally occurring phenomena. Data collection occurred via two web-based surveys administered at different points in time. Hypothesized relationships were tested utilizing correlational and hierarchical moderated multiple regression analyses. The findings of this dissertation suggest that traits, such as personality and cognitive ability, are not associated with leader emergence in virtual workgroups. In addition, the results indicate that the exhibition of relationship-oriented leader behaviors enhances group identity. In turn, identification is associated with increases in perceptions of leader effectiveness and decreases in counterproductive behavior exhibited by group members. This dissertation exposes an important limitation to the application of trait leadership theory. It also demonstrates the importance of relationship-oriented behavior and social identity in virtual contexts. Further, it advances an integrative theoretical model for the study of virtual workgroup phenomena. These contributions should assist and inform other researchers, as well as practitioners, interested in leadership and group member behavior in virtual workgroups.