Stomata are microscopic pore-like structures on the surface of leaves, that regulate the exchange of moisture and gas between plants and the atmosphere. The distribution of stomata depends on the living environment and growth characteristics of vegetable crops. Each stoma consists of two guard cells, and the guard cells control the stomatal motion, such as opening and closing. The movement of stomata plays vital roles in the growth and development of vegetable crops, such as photosynthesis, respiration, transpiration, resistance to abiotic and biotic stresses, and signal transmission. When receiving the signal of environmental change, including moisture, light, temperature, and the concentration of carbon dioxide, guard cells affect stomatal movement by regulating themselves. Phytohormones participate in the internal molecular regulatory mechanism to regulate the movement of stomata. This chapter summarizes the characteristics and regulatory mechanism of stomatal motion in horticultural crops, focusing on the role of phytohormones, and puts forward the challenges and opportunities in stomatal regulation for enhancing vegetable production and postharvest management.