Issues of global environmental change, global health, emerging disease, and sustainability present some of the most complex challenges of the twenty-first century. Individual disciplines cannot address these issues in isolation. Proactive, innovative, and trans-disciplinary solutions are required. Recognizing the inherent connectedness of humans, animals, plants, and their shared environment, One Health encourages the collaboration of many disciplines-including human and veterinary medicine, public health, social science, public policy, environmental science, and others-to address global and local health challenges. Despite great progress in this shift toward transdisciplinarity, the environmental component of the One Health paradigm remains underrepresented in One Health discourse. Human and animal health issues are commonly discussed under the umbrella of the One Health paradigm, while upstream environmental drivers and solutions are less prominent. We assessed the current integration of environmental issues in One Health publications and leadership. There is room for enhanced integration of environmental knowledge in the implementation of One Health approaches. We discuss the potential benefits from the collaboration between One Health and ecohealth, and explore strategies for increased environmental involvement.