This self-study module is part of the series ‘Introduction to Plant Biology’ and introduces plant hormones, explaining how chemical signaling enables communication and coordination within plants. It is designed for students learning basic plant biology and for teachers seeking clear figures and explanations for educational use. The module covers fundamental concepts of cell signaling and signal transduction and examines the functions and interactions of major plant hormones, including auxin, cytokinin, abscisic acid, gibberellins, ethylene, salicylic acid, jasmonic acid, brassinosteroids, and strigolactones, in regulating plant growth, development, and responses to the environment.