This special issue of the *Annals of Botany* focuses on plant responses to water stress, covering recent advancements at the molecular level, through photosynthesis and metabolism, to their application in crop selection and yield. The issue highlights the importance of understanding water deficits, particularly given the significant developments in this area over the past decade. Key topics include the molecular and physiological processes involved in water stress, such as the regulation of genes and signaling pathways, and their impact on photosynthesis and metabolism. The issue also discusses the contrasting interpretations of "stomatal" and "non-stomatal" inhibition of photosynthesis under water stress, emphasizing the need for further research to resolve these discrepancies. Additionally, it explores how these responses translate into field conditions, affecting plant growth, development, and yield components. The issue concludes by discussing the implications for crop selection and the potential for using quantitative trait loci analysis to link genetic variations to specific physiological responses.This special issue of the *Annals of Botany* focuses on plant responses to water stress, covering recent advancements at the molecular level, through photosynthesis and metabolism, to their application in crop selection and yield. The issue highlights the importance of understanding water deficits, particularly given the significant developments in this area over the past decade. Key topics include the molecular and physiological processes involved in water stress, such as the regulation of genes and signaling pathways, and their impact on photosynthesis and metabolism. The issue also discusses the contrasting interpretations of "stomatal" and "non-stomatal" inhibition of photosynthesis under water stress, emphasizing the need for further research to resolve these discrepancies. Additionally, it explores how these responses translate into field conditions, affecting plant growth, development, and yield components. The issue concludes by discussing the implications for crop selection and the potential for using quantitative trait loci analysis to link genetic variations to specific physiological responses.