Phytosulfokine (PSK) peptides are disulfated pentapeptides that function as plant peptide hormones. Four bioactive PSKs—PSK-α, -γ, -δ, and -ε—have been identified and are involved in plant growth, development, and immunity. PSKs are encoded by precursor genes found in higher plants and undergo tyrosine sulfation and proteolytic cleavage to become active. PSK signaling is mediated by plasma membrane-localized receptors (PSKRs) belonging to the leucine-rich repeat receptor-like kinase family. PSKs have multiple biological functions, including promoting cell division and growth, regulating plant reproduction, inducing somatic embryogenesis, enhancing legume nodulation, and regulating resistance to biotic and abiotic stress. This review summarizes recent advances in PSK biosynthesis, signaling, and function, highlighting their roles in plant development and stress responses. PSK signaling involves complex interactions with co-receptors and downstream signaling pathways, including calcium signaling and cyclic GMP (cGMP) production. PSKs also play a role in plant immunity, with PSK signaling modulating resistance to both biotrophic and necrotrophic pathogens. Additionally, PSKs contribute to plant growth and development by regulating cell wall remodeling and expansion. The review also discusses the potential applications of PSKs in agriculture and biotechnology. Future research should focus on understanding the mechanisms of PSK maturation and signaling, as well as the interactions between PSK and other phytohormones.Phytosulfokine (PSK) peptides are disulfated pentapeptides that function as plant peptide hormones. Four bioactive PSKs—PSK-α, -γ, -δ, and -ε—have been identified and are involved in plant growth, development, and immunity. PSKs are encoded by precursor genes found in higher plants and undergo tyrosine sulfation and proteolytic cleavage to become active. PSK signaling is mediated by plasma membrane-localized receptors (PSKRs) belonging to the leucine-rich repeat receptor-like kinase family. PSKs have multiple biological functions, including promoting cell division and growth, regulating plant reproduction, inducing somatic embryogenesis, enhancing legume nodulation, and regulating resistance to biotic and abiotic stress. This review summarizes recent advances in PSK biosynthesis, signaling, and function, highlighting their roles in plant development and stress responses. PSK signaling involves complex interactions with co-receptors and downstream signaling pathways, including calcium signaling and cyclic GMP (cGMP) production. PSKs also play a role in plant immunity, with PSK signaling modulating resistance to both biotrophic and necrotrophic pathogens. Additionally, PSKs contribute to plant growth and development by regulating cell wall remodeling and expansion. The review also discusses the potential applications of PSKs in agriculture and biotechnology. Future research should focus on understanding the mechanisms of PSK maturation and signaling, as well as the interactions between PSK and other phytohormones.