Progesterone, a steroid hormone widely recognized for its pivotal roles in mammalian biology, has garnered increasing attention in recent years for its physiological functions in plants. This paper aims to provide a comprehensive overview of progesterone’s regulatory influence on plant growth, development, and stress responses, while also delving into its metabolism within plant systems. Notably, progesterone is present across all plant species, and even at low concentrations, it exerts control over a broad spectrum of physiological activities. Due to its functional overlap with known plant hormones, progesterone is emerging as a potential candidate for inclusion in the plant hormone category. Widespread research has demonstrated progesterone’s ability to stimulate plant growth, enhance seed germination, and bolster resistance to various abiotic stresses, including drought, salinity, extreme temperatures, and pre- and postharvest physiological disorders. These protective and growth-promoting effects suggest that progesterone holds significant potential for agricultural applications, particularly in stress management and crop productivity enhancement. However, while many studies have explored progesterone’s physiological roles in plants, its underlying molecular mechanisms remain largely uncharted. Future research at the molecular level is essential to fully elucidate progesterone signaling pathways and to uncover the intricate processes by which this hormone regulates plant functions.