As the older population continues to grow in the US so does the burden imposed on the health care system due to the rise in the prevalence of Alzheimer's disease and related dementias (ADRD), representing one of the greatest challenges facing the public health. To date, there are no effective treatments for ADRD and thus identifying dietary strategies that would help prevent or mitigate ADRD is of great priority. Evidence on the role of flavonoids, natural pigments found in a wide range of plant-based foods, in ADRD risk is inconsistent due to the many limitations associated with the current studies. Accordingly, this study aimed to more accurately explore the relationship between total and the six classes of flavonoids and risk of ADRD while taking into account the limitations of previous studies. We found that individuals with higher intakes of the three flavonoid classes: flavonols, anthocyanins, and flavonoid polymers had a lower risk of ADRD compared to those with lower intakes. Our results add to the limited evidence that flavonoids could have the potential to reduce the risk of ADRD.