The two-way interaction of food (poly)phenols with the human gut microbiota has been studied throughout the past ten years. Research has shown that this interaction can be relevant to explain the health effects of these phytochemicals. The effect of the food matrix and food processing on this interaction has only been partially studied. In this article, the studies within this field have been critically reviewed, with a special focus on the following groups of phenolic metabolites: citrus flavanones, pomegranate ellagitannins, and cocoa proanthocyanidins. The available research shows that both the food matrix and food processing can be relevant factors for gut microbiota reshaping to reach a healthier microbial ecology and for the conversion of polyphenols to bioactive and bioavailable metabolites. There are, however, some research gaps that indicate a more comprehensive research approach is needed to reach valid conclusions regarding the gut microbiota–mediated effects of polyphenols on human health.