Non-alcoholic fatty liver disease and colonic diverticulosis are widespread, obesity-related diseases. It has recently become clear that non-alcoholic fatty liver disease is a systemic disease and may play a key role in metabolic syndrome; therefore, the term metabolic-dysfunction-associated fatty liver disease has been introduced in the literature. Excess visceral adipose tissue is an important predictor of complications in both non-alcoholic fatty liver disease and colonic diverticulosis. Current evidence suggests that intestinal dysbiosis may be involved in the development of both non-alcoholic fatty liver disease and colonic diverticulosis, and that metabolic syndrome is a consequence rather than a cause of this complex relationship. In this review, our aim was to assess the current knowledge of the complex interplay between metabolic syndrome, non-alcoholic fatty liver disease, and colonic diverticulosis.