The human skin is a crucial organ that protects the organism from the outer environment. Skin integrity and health depend on both extrinsic and intrinsic factors. Intrinsic factors such as aging and genetic background contribute to weakened skin and disease susceptibility. Meanwhile, extrinsic factors including UV radiation, pollution, smoking, humidity, and poor diet also affect skin health and disease. On the other hand, healthy dietary patterns such as plant-based diets have gained popularity as a complementary therapy for skin health. A plant-based diet is defined as all diets based on plant foods, including an abundance of vegetables, fruits, beans, lentils, legumes, nuts, seeds, fungi, and whole grains, with limited or no animal products or processed foods. However, some authors also exclude or limit processed foods in the definition. Recent research has shown that these diets have beneficial effects on inflammatory skin diseases. This review explored the beneficial effects of plant-based diets on inflammatory skin diseases and plant-based functional foods on healthy skin. In conclusion, plant-based diets and plant-based functional foods may have beneficial effects on skin health through the gut microbiome.