Quinoa is an ancestral Andean grain of great importance due to its nutritional potential, cultivated in the Andean region for many years. Lactic acid fermentation may be a cost-effective processing alternative to improve quinoa-derived or gluten-free products, as it has been used in different cereals to enhance physicochemical and sensory characteristics. This review presents the nutritional importance of quinoa, the key indicators that can affect homofermentation, the analysis of different studies that have worked with this pseudocereal as a substrate for the development of various fermented products such as sourdoughs from quinoa flour for bread and other baked goods, beverages, pasta, baked products in combination with other pseudocereals and buckwheat, and soy-based beverages. The results reveal that quinoa is a nutrient-rich substrate for lactic acid bacteria, and fermentation generates nutritional changes by increasing certain macronutrients and/or bioactive compounds through bacterial metabolism and starch hydrolysis. Additionally, it improves functional, technological, and sensory properties due to starch modification and metabolite production. This presents a promising alternative in quinoa processing and the development of functional foods.