Basil (Ocimum basilicum L.) is found worldwide and is used in the food, pharmaceutical, and cosmetic industries; however, the nutritional and functional properties of the seeds are scarcely known. Basil seeds contain high concentrations of proteins (11.4–22.5 g/100 g), with all the essential amino acids except S-containing types and tryptophan; dietary fiber (soluble and insoluble) ranging from 7.11 to 26.2 g/100 g lipids, with linoleic (12–85.6 g/100 g) and linolenic fatty acids (0.3–75 g/100 g) comprising the highest proportions; minerals, such as calcium, potassium, and magnesium, in high amounts; and phenolic compounds, such as orientine, vicentine, and rosmarinic acid. In addition, their consumption is associated with several health benefits, such as the prevention of type-2 diabetes, cardio-protection, antioxidant and antimicrobial effects, and anti-inflammatory, antiulcer, anticoagulant, and anti-depressant properties, among others. The focus of this systematic review was to study the current state of knowledge and explore the enormous potential of basil seeds as a functional food and source of functional ingredients to be incorporated into foods.