The term “One Health” describes the inter-dependent balance that exists around the world between the health of people, animals and the environment. The concept arose in 2003 in response to the emergence of the H5N1 strain of avian influenza virus causing severe human respiratory disease. Previously, policy and attention had been directed towards specific issues affecting human, animal, plant or ecosystem health separately from each other. This independent scientific approach is still necessary to ensure depth to scientific advances in understanding of specific factors influencing human, animal and environmental health. However, it fails to address interdisciplinary, global sustainability challenges surrounding: livestock and crop production efficiency; the emergence of new infectious diseases; antimicrobial and antiparasitic drug resistance; food safety; environmental degradation; or adverse impacts of climate change. Addressing the full spectrum of these challenges at local, regional and international levels requires an integrated approach that links humans, animals and the environment. Solutions must be holistic, and need to take into account complementary benefits, opportunities, risks and trade-offs of human, animal and environmental interventions.