Both “political ecology” and “resilience” (or socio-ecological systems) are research approaches that explicitly claim to be inter- or even post-disciplinary. Both of these “interdisciplines” are currently dominant in academic study of society-environment interactions, engaging sizeable communities of students and scholars drawn from a range of traditional disciplines. Both approaches seeks to facilitate the kinds of boundary crossings that are crucial at the interface of nature and society, leading to new insights and knowledge, and to solving problems that are not contained within the boundaries. Yet there are inevitably pressures to “discipline” the new “interdisciplines”. In the case of political ecology and resilience, each has separate intellectual traditions, with some fundamental differences in purpose, in epistemology, in explanatory tools, and in ideology – illustrating that there are multiple ways of being interdisciplinary. This chapter explores these differences and reflects on the meaning of interdisciplinarity.