Quinoa (Chenopodium quinoa Willd.) grain is often eaten worldwide as a healthy food, but consuming nutrient-rich quinoa leaves as a leafy green vegetable is uncommon. This study evaluated the potentiality of leafy green quinoa as a major source of protein, amino acids, and minerals in the human diet. Also, the study compared the nutrient content of quinoa leaves with those of amaranth and spinach leaves. The proximate analysis of quinoa dry leaves showed a higher amount (g/100 g dry weight) of protein (37.05) than amaranth (27.45) and spinach (30.00 g). Furthermore, a lower amount of carbohydrate (34.03) was found in quinoa leaves compared to amaranth (47.90) and spinach (43.78 g). A higher amount of essential amino acids was found in quinoa leaves relative to those of amaranth and spinach. The highest amounts (mg/100 g dry weight) of minerals in quinoa dry leaves were copper (1.12), manganese (26.49), and potassium (8769.00 mg), followed by moderate amounts of calcium (1535.00), phosphorus (405.62), sodium (15.12), and zinc (6.79 mg). Our findings suggest that quinoa leaves can be consumed as a green vegetable with an excellent source of nutrients. Therefore, we endorse the inclusion of quinoa in the leafy green vegetable group.