Flavonoids are small molecular secondary metabolites synthesized by plants, playing crucial roles in various biological activities. They exhibit strong antioxidative properties, which contribute to their functions in plant protection against biotic and abiotic stresses. Flavonoids also serve as regulators in symbiotic interactions with microorganisms, such as nitrogen-fixing bacteria and mycorrhizal fungi. Additionally, they participate in allelopathic interactions between plants, influencing the growth and development of other plants. In response to environmental stresses, flavonoids protect plants by scavenging reactive oxygen species (ROS) and maintaining the redox state in cells. They can also act as attractants or deterrents to insects, influencing their behavior and growth. Flavonoids are increasingly being explored for their potential in agriculture, medicine, and cosmetology due to their natural origin and lack of adverse effects. The review highlights the current knowledge on the functions of flavonoids in plant physiology and their interactions with the environment, emphasizing their regulatory and signaling roles.Flavonoids are small molecular secondary metabolites synthesized by plants, playing crucial roles in various biological activities. They exhibit strong antioxidative properties, which contribute to their functions in plant protection against biotic and abiotic stresses. Flavonoids also serve as regulators in symbiotic interactions with microorganisms, such as nitrogen-fixing bacteria and mycorrhizal fungi. Additionally, they participate in allelopathic interactions between plants, influencing the growth and development of other plants. In response to environmental stresses, flavonoids protect plants by scavenging reactive oxygen species (ROS) and maintaining the redox state in cells. They can also act as attractants or deterrents to insects, influencing their behavior and growth. Flavonoids are increasingly being explored for their potential in agriculture, medicine, and cosmetology due to their natural origin and lack of adverse effects. The review highlights the current knowledge on the functions of flavonoids in plant physiology and their interactions with the environment, emphasizing their regulatory and signaling roles.