In this article, the authors lay the foundation for the emerging area of research on online protest tactics mobilized against business. The authors offer a definition of online business protest tactics and distinguish them from related activities such as electronic civil disobedience and cybercrime. They also appeal to the interest-group literature as one theoretical foundation for this area of research. Based on the degree to which each tactic involves intrusion, disruption, or damage, the authors categorize the array of online business protest tactics into a typology, providing definitions and illustrative examples from the business press for each. They advance a dualistic framework to evaluate the intermediate and ultimate effectiveness of the various online business protest tactics using a set of criteria relevant to both online and off-line environments, and conclude by suggesting avenues for future research.