Animal behaviour and welfare research are part of a wider endeavour to optimize the health and wellbeing of humans, animals and ecosystems. As such, it is part of the One Health research agenda. This article applies ethical principles described by the One Health High Level Expert Panel to animal behaviour and welfare research. These principles entail that animal behaviour and welfare research should be valued equitably alongside other research in transdisciplinary and multisectoral collaboration. It should include and promote a multiplicity of marginalized voices, including those of animals, and it should apply and describe a harmonious balance between human--animal-environment interactions. Lastly, it should describe how humans need to change behaviour, adopt sustainable solutions and recognize the importance of animal welfare and the integrity of the whole ecosystem.