Disagreement on which theory of collective behavior best predicts or explains how crowd processes work prompted this case study. By closely examining, through participant observation, the unfolding of one episode of nonviolent collective behavior at a professional football game, four frequently applied theories of collective behavior are tested for their utility in sports crowd situations. Each theory is assessed for strengths and weaknesses. Findings show contagion theory, convergence theory, emergent norm theory, and value-added theory all valuable in explaining some facets of observed spectator behavior; therefore a synthesis of theories might prove more useful than applying theories separately. A methodological problem emerged during evaluation, concerning difficulty in distinguishing among the indicators for each theory. Several overlapping theoretical concepts confounded attempts to operationalize unique empirical measures and hence, to compare the theories satisfactorily. Further research is needed to provide adequate measures.