Eucalyptus is one of the world's most widely planted hardwood genera and is increasingly cultivated in environments where water availability constrains productivity. Research on eucalypt drought responses is extensive but fragmented across morphology, gas exchange, tissue water relations, hydraulics, nutrition, metabolites and molecular responses. This review integrates field, nursery and controlled-environment evidence to develop a multi-axis framework linking water access, stomatal regulation, tissue tolerance and xylem safety with potassium (K), phosphorus (P), sodium (Na), elevated CO₂ and heat. The synthesis indicates that drought performance cannot be represented by a single tolerance trait: genotypes may avoid dehydration through deep water access and stomatal control, tolerate low water potentials through osmotic or elastic adjustment, or maintain function through resistant xylem. K is a particularly important modifier because it can increase photosynthesis, leaf area, transpiration and water-use efficiency for stemwood production, while simultaneously increasing water demand and, under some conditions, narrowing hydraulic safety margins. P limitation can constrain growth and the response to elevated CO₂, whereas combined drought and heat generate responses that are not predictable from either stress alone. Across the literature, inference is weakened by short experiments, restricted root volume, single-clone comparisons, small sample sizes and limited integration of nutrition with hydraulics. We propose a research agenda centred on replicated factorial field experiments, explicit hydraulic endpoints, genotype × nutrition × water interactions, recovery and repeated-stress measurements, and process-based models that couple carbon, water and nutrient cycles.