Temperature plays a critical role in animal survival and climate warming is one of the greatest threats to global biodiversity in the future. It is already affecting species and communities with severe impacts and it is predicted that climate warming will cause species extinctions and distributional shifts in the coming decades. The impact of climate warming is expected to be particularly severe on ectothermic animals, including fishes, amphibians, and reptiles. Thus, assessing species’ responses to ongoing climate warming and determining what conservation actions should be taken are among the most significant and controversial challenges for ecologists. Identifying the most vulnerable species to extinction as a result of climate warming is an appropriate first step in mitigating the impacts of a changing world. An organism’s vulnerability to climate warming depends on its sensitivity to environmental changes, its exposure to the change, and its ability to recover from and potential to adapt to change. The interaction of these factors makes predicting the effects of climate warming on species a complex and major challenge for ecologists. Developing a deeper knowledge of ectotherms’ vulnerability to climate warming is crucial to enhance our understanding of extinction processes and significantly contribute to conservation efforts by guiding the implementation of better policies and management strategies to prevent the extinction of remaining populations. Investigations of climate warming vulnerability are likely to benefit from measurements of environmental conditions taken at the scale at which organisms experience them. Therefore, the main objective of this interdisciplinary Research Topic is to bring together research on how ectotherms respond to climate warming at various levels. We will particularly focus on the life-history, energy strategy, physiological response, etc. We encourage inter-and multidisciplinary research approaches linking molecular biology, thermal physiology (and ecology), behavioral ecology, functional ecology, evolutionary genetics, and bioenergetics.