We provide a simple model for considering the interaction between multiple legal regimes existing simultaneously within a single jurisdiction. We demonstrate that, even when the fundamental relationship between outputs of such regimes is to behave as substitutes for one another, the existence of negative externalities between the enforcement technologies can result in the withdrawal of enforcement efforts. We term this phenomenon legal dissonance – the situation in which legal regimes interact negatively in their production technologies. This reduction in aggregate enforcement efforts can result in high levels of crime and disorder within the pluralistic society. This model is then demonstrated in regard to the post-colonial state of Papua New Guinea where significant negative production externalities are present, enforcement levels are low, and levels of crime and disorder are high. Survey data is introduced to demonstrate that these outcomes are in part attributable to the co-existence of the customary legal regime providing for “payback killing” with the overlaid state regime criminalising the same. Disorder may be the outcome of too much law.