This article examines the concept, development and implementation of the no harm principle and its wider role in public international law. While generally acknowledged in international environmental law protecting other states from physical harm caused to their territory, in other areas of international law the principle is of increasing importance in order to find a balancing mechanism between colliding states’ interest in case of negative externalities caused by one state to the detriment of other states. The article traces implementations of the regulatory mechanism to focus on the adverse effect in other areas of public international law, ranging from trade and monetary agreements to invocation of the concept in current initiatives especially in the context of harmful tax competition and banking regulations. This will show the general capability to balance colliding states’ interest providing solutions for an increasingly interdependent world and giving meaning to the concept of a global community.