Abstract <p>Phosphorus (P) and copper (Cu) interact in soils through a network of physical, chemical and biological processes that regulate their speciation, mobility, and bioavailability. Direct P–Cu interactions primarily occur via adsorption and complexation mechanisms. P addition modifies soil surface charge and promotes ligand exchange as well as the formation of stable ternary complexes leading to Cu immobilization. In parallel, the precipitation of CuPO₄ mineral phases provides an additional pathway for Cu stabilization in soils. Meanwhile, P–Cu relationship influences soil microbial communities and enzymatic activities, thereby affecting nutrient cycling and transformation processes. However, P–Cu interaction does not universally immobilize Cu, as competitive sorption between these elements can lead to Cu displacement and increased solubility under certain conditions. These contrasting outcomes highlight the context-dependence of P–Cu interactions. Furthermore, the relationship of these elements are strongly modulated by soil pH, mineralogy, P source and application rate. This article synthesizes current knowledge of P–Cu interactions and highlights key research gaps and opportunities necessary for developing more precise, evidence-based P–Cu management in soil resources.</p>