In this article, we aimed to evaluate the utility of critical posthumanism for nurses interested in planetary health—a growing area of study that requires a decentering of the human, and environmental justice considerations. We used Chinn and colleagues' method to describe and critically reflect on critical posthumanism, extending the theory analysis method to include a wide range of academic and video sources. We found that critical posthumanism is like a double‐edged sword: It provides a lens through which to transcend human‐centric (...) approaches to healthcare but is marred by its lack of clarity and inaccessibility. We argue critical posthumanism can be adapted to enhance its potential at the intersection of nursing and planetary health. An analysis of critical posthumanism is followed by a discussion framed by five ways of knowing in nursing, highlighting real‐world examples of how critical posthumanism can aid nurses in dealing with planetary health concerns. By exploring the intersections of critical posthumanism with nursing knowledge, we demonstrate how critical posthumanism can enable nurses to comprehend and tackle environmental issues intricately linked to human health. (shrink)