This thesis examines the history, development, theory, and practice of distributed denial of service actions as a tactic of political activism. DDOS actions have been used in online political activism since the early 1990s, though the tactic has recently attracted significant public attention with the actions of Anonymous and Operation Payback in December 2010. Guiding this work is the overarching question of how civil disobedience and disruptive activism can be practiced in the current online space. The internet acts as a vital arena of communication, self expression, and interpersonal organizing. When there is a message to convey, words to get out, people to organize, many will turn to the internet as the zone of that activity. Online, people sign petitions, investigate stories and rumors, amplify links and videos, donate money, and show their support for causes in a variety of ways. But as familiar and widely accepted activist tools—petitions, fundraisers, mass letter-writing, call-in campaigns and others—find equivalent practices in the online space, is there also room for the tactics of disruption and civil disobedience that are equally familiar from the realm of street marches, occupations, and sit-ins? This thesis grounds activist DDOS historically, focusing on early deployments of the tactic as well as modern instances to trace its development over time, both in theory and in practice. Through that examination, as well as tool design and development, participant identity, and state and corporate responses, this thesis presents an account of the development and current state of activist DDOS actions. It ends by presenting an analytical framework for the analysis of activist DDOS actions.