Plant hormones play crucial roles in regulating developmental processes and signaling networks involved in plant responses to biotic and abiotic stresses. Significant progress has been made in understanding the roles of salicylic acid (SA), jasmonates (JA), and ethylene (ET) in plant responses to biotic stresses. Other hormones, such as abscisic acid (ABA), auxin, gibberellic acid (GA), cytokinin (CK), brassinosteroids (BR), and peptide hormones, are also involved in plant defence, but their roles are less well studied. This review summarizes recent advances in understanding the role of these hormones in modulating plant defence responses against diseases and pests. Plants are exposed to a wide variety of pathogens, including fungi, oomycetes, bacteria, viruses, and nematodes. These pathogens deliver effector molecules into plant cells to promote disease. Plants have complex defence mechanisms, including preformed physical and chemical barriers and inducible defence mechanisms triggered by pathogen recognition. These include oxidative burst, expression of defence-related genes, production of antimicrobial compounds, and programmed cell death. Plants use a basal defence mechanism, also called the innate immune system, to defend against most microbial pathogens. The plant immune system is represented as a 'zigzag' model, where perception of microbial or pathogen-associated molecular patterns (MAMPs or PAMPs) by pattern recognition receptors (PRRs) results in PAMP-triggered immunity (PTI). Successful pathogens suppress PTI and induce effector-triggered susceptibility (ETS), while plants activate effector-triggered immunity (ETI) to resist disease. Plants produce various hormones, including auxins, gibberellins, abscisic acid, cytokinins, salicylic acid, ethylene, jasmonates, brassinosteroids, and peptide hormones. Recent studies have identified strigolactones as a new class of plant hormones. These hormones play important roles in growth, development, and stress responses. Infection with pathogens changes the levels of various phytohormones, and the identification of mutants affected in hormone biosynthesis, perception, and signal transduction has helped understand their roles in plant defence. SA, JA, and ET are major phytohormones involved in plant defence against pathogens and abiotic stresses. SA is crucial for defence against biotrophic and hemi-biotrophic pathogens and the establishment of systemic acquired resistance (SAR). JA and ET are usually associated with defence against necrotrophic pathogens and herbivorous insects. While SA and JA/ET pathways are generally antagonistic, synergistic interactions have also been reported. The defence signaling network depends on the pathogen's nature and mode of pathogenicity. Plants employ complex regulatory mechanisms to trigger effective defence responses against various pathogens and pests. The interaction between SA and JA/ET pathways may be regulated depending on the specific pathogen.Plant hormones play crucial roles in regulating developmental processes and signaling networks involved in plant responses to biotic and abiotic stresses. Significant progress has been made in understanding the roles of salicylic acid (SA), jasmonates (JA), and ethylene (ET) in plant responses to biotic stresses. Other hormones, such as abscisic acid (ABA), auxin, gibberellic acid (GA), cytokinin (CK), brassinosteroids (BR), and peptide hormones, are also involved in plant defence, but their roles are less well studied. This review summarizes recent advances in understanding the role of these hormones in modulating plant defence responses against diseases and pests. Plants are exposed to a wide variety of pathogens, including fungi, oomycetes, bacteria, viruses, and nematodes. These pathogens deliver effector molecules into plant cells to promote disease. Plants have complex defence mechanisms, including preformed physical and chemical barriers and inducible defence mechanisms triggered by pathogen recognition. These include oxidative burst, expression of defence-related genes, production of antimicrobial compounds, and programmed cell death. Plants use a basal defence mechanism, also called the innate immune system, to defend against most microbial pathogens. The plant immune system is represented as a 'zigzag' model, where perception of microbial or pathogen-associated molecular patterns (MAMPs or PAMPs) by pattern recognition receptors (PRRs) results in PAMP-triggered immunity (PTI). Successful pathogens suppress PTI and induce effector-triggered susceptibility (ETS), while plants activate effector-triggered immunity (ETI) to resist disease. Plants produce various hormones, including auxins, gibberellins, abscisic acid, cytokinins, salicylic acid, ethylene, jasmonates, brassinosteroids, and peptide hormones. Recent studies have identified strigolactones as a new class of plant hormones. These hormones play important roles in growth, development, and stress responses. Infection with pathogens changes the levels of various phytohormones, and the identification of mutants affected in hormone biosynthesis, perception, and signal transduction has helped understand their roles in plant defence. SA, JA, and ET are major phytohormones involved in plant defence against pathogens and abiotic stresses. SA is crucial for defence against biotrophic and hemi-biotrophic pathogens and the establishment of systemic acquired resistance (SAR). JA and ET are usually associated with defence against necrotrophic pathogens and herbivorous insects. While SA and JA/ET pathways are generally antagonistic, synergistic interactions have also been reported. The defence signaling network depends on the pathogen's nature and mode of pathogenicity. Plants employ complex regulatory mechanisms to trigger effective defence responses against various pathogens and pests. The interaction between SA and JA/ET pathways may be regulated depending on the specific pathogen.