Human reactions to conservation interventions can trigger unintended feedbacks resulting in poor conservation outcomes. Understanding unintended feedbacks is a necessary first step toward the diagnosis and solution of environmental problems, but existing anecdotal evidence cannot support decision-making. Using conservation examples, we present a conceptual framework and typology of unintended feedbacks based on a social-ecological systems (SES) approach. Three types of causal mechanisms for unintended feedbacks are distinguished: (1) flow unintended feedbacks when pre-existing feedbacks are enhanced or dampened; (2) deletion unintended feedbacks; and (3) addition unintended feedbacks when interventions, respectively, remove or add actors or links to the SES structure. Application of this typology can improve conservation outcomes by enabling the inclusion of complex relationships into planning and evaluation. We show how widely used tools for conservation planning could produce misleading recommendations, and discuss future work to mitigate the effect of unintended feedbacks in conservation practice. There is an urgent need to collect evidence in a structured way in order to understand the mechanisms by which human decision-making feeds through to conservation outcomes at different scales, thereby minimizing negative unintended feedbacks. The framework presented in this article can support the development of this evidence-base. Copyright