Although great advances have been made in the discovery of new drugs that effectively penetrate the brain and alleviate neurological disorders, such as Alzheimer's disease, Parkinson's disease and Autism Spectrum Disorder, current pharmacological treatment options are unable to eradicate these diseases. The growing awareness of a bidirectional communication between the brain and the intestinal compartment, with particular focus on the role played by the gut microbiota in the gut-brain binomial, has opened new avenues for the investigation of the molecular mechanisms underlying those neurological diseases and, consequently, for the discovery of a new generation of disease-modifying strategies. We present an overview of the evidence supporting the importance of dysbiosis in the development of intestinal and neurological diseases. In addition, the usefulness of dietary polyphenols in managing disorders, via modulation of the microbiota-gut-brain axis, is discussed. Dietary polyphenols are increasingly envisaged as a novel and a relevant strategy in the prevention and treatment of neurological disorders. This is explained not only by their ability to reduce neuroinflammation and to improve memory and cognitive function, but also by their ability to modulate the gut microbiota, which makes them promising nutraceuticals to combat brain disorders.