Flavonoids, a class of polyphenols, have shown potential as biopesticides in crop protection due to their ability to interfere with insect physiology. This review summarizes current research on flavonoids as insecticides, focusing on their modes of action, structural-activity relationships, and challenges in application. Flavonoids are abundant in plants and have diverse biological functions, including defense against pests and pathogens. They are considered safer and more sustainable alternatives to traditional pesticides, which have led to environmental and health concerns. Flavonoids can act as feeding deterrents by inhibiting key digestive enzymes in insect midguts, such as amylases, glycosidases, lipases, and proteases. They can also disrupt detoxification systems by affecting enzymes like glutathione S-transferase and esterase, leading to oxidative stress and increased toxicity. Additionally, flavonoids can delay insect development, induce malformations, and affect reproductive cycles by altering the pre-reproductive period and reducing fecundity. Some flavonoids inhibit acetylcholinesterase, a key enzyme in insect physiology, which can lead to paralysis and death. Flavonoids also target the nervous system by affecting neuronal channels and enzymes, such as acetylcholinesterase, which is crucial for cholinergic neurotransmission. Their ability to inhibit chitinolytic enzymes, which are essential for insect exoskeleton formation, further contributes to their insecticidal activity. Despite their potential, flavonoids face challenges in commercialization, including their toxicity to non-target organisms and their biodegradability in soil. Research is ongoing to improve their efficacy and reduce environmental impact through encapsulation in biodegradable polymers and the development of targeted delivery systems. The review highlights the need for further studies to address these challenges and to fully understand the mechanisms of flavonoid action, ensuring their safe and effective use in sustainable pest management.Flavonoids, a class of polyphenols, have shown potential as biopesticides in crop protection due to their ability to interfere with insect physiology. This review summarizes current research on flavonoids as insecticides, focusing on their modes of action, structural-activity relationships, and challenges in application. Flavonoids are abundant in plants and have diverse biological functions, including defense against pests and pathogens. They are considered safer and more sustainable alternatives to traditional pesticides, which have led to environmental and health concerns. Flavonoids can act as feeding deterrents by inhibiting key digestive enzymes in insect midguts, such as amylases, glycosidases, lipases, and proteases. They can also disrupt detoxification systems by affecting enzymes like glutathione S-transferase and esterase, leading to oxidative stress and increased toxicity. Additionally, flavonoids can delay insect development, induce malformations, and affect reproductive cycles by altering the pre-reproductive period and reducing fecundity. Some flavonoids inhibit acetylcholinesterase, a key enzyme in insect physiology, which can lead to paralysis and death. Flavonoids also target the nervous system by affecting neuronal channels and enzymes, such as acetylcholinesterase, which is crucial for cholinergic neurotransmission. Their ability to inhibit chitinolytic enzymes, which are essential for insect exoskeleton formation, further contributes to their insecticidal activity. Despite their potential, flavonoids face challenges in commercialization, including their toxicity to non-target organisms and their biodegradability in soil. Research is ongoing to improve their efficacy and reduce environmental impact through encapsulation in biodegradable polymers and the development of targeted delivery systems. The review highlights the need for further studies to address these challenges and to fully understand the mechanisms of flavonoid action, ensuring their safe and effective use in sustainable pest management.