Almost everyone agrees that violence can sometimes be justified, but if it is to be justified it must be proportionate. Whether we are discussing war, self-defence, punishment, human rights law, protest, or free speech, most philosophers agree that inflicted harms or incursions into our most basic rights must be proportionate. Violence in Proportion closely examines this widely held proportionality principle, focusing on situations in which inflicted harm prevents harm to others. It finds that lurking beneath our surface agreement that violence must be proportionate, there are many philosophically knotty problems that we must address. The book uncovers, explores, and offers solutions to these problems. This is the first philosophical monograph dedicated to the study of this important concept. The book begins by mapping different species of proportionality, and the limits of their application. Focusing on a specific type of proportionality that Tomlin calls preventive limiting proportionality, Violence in Proportion goes on to explore puzzles concerning counterfactual baselines, proportionality under uncertainty, whether and when to continue a disproportionate course of conduct, the relationship between the proportionality of acts and courses of conduct, and aggregation. The book seeks to do three things: uncover and explain the philosophical puzzles that a commitment to a proportionality limit on violence and harm gives rise to; map out various positions that we may take in response to these puzzles; and to argue for certain responses, and in so doing build a novel account of proportionality. Along the way, Tomlin shows us how complex this seemingly simple idea is.