<p>The chia seeds have high nutritional value and promising bioactive profile. The demand for chia oil is increasing globally due to its wide use in the food, medical, pharmaceutical, and cosmetic industries. The chia seed cake (CSC), a by-product of oil processing industries, holds significant potential as a functional ingredient due to its rich nutritional and bioactive profile. The CSC is nutrient-dense, with high protein, fiber, and essential amino acid content, alongside an impressive profile of phenolic compounds and flavonoids, contributing to its strong antioxidant capacity. The phenolic compounds present in CSC include phenolic acids (rosmarinic, chlorogenic, gallic, and caffeic acid) and flavonoids (rutin, quercetin, and kaempferol). This study reviewed the chemical composition, phenolic content, and antioxidant activity of CSC, highlighting its potential applications in food and nutraceutical industries. The information provided in studies underscore the multifunctional benefits of CSC, including its cardiovascular, antimicrobial, anti-inflammatory, and anti-diabetic properties. The valorization of CSC not only promotes environmental sustainability by minimizing agro-industrial waste but also offers innovative opportunities for developing health-promoting functional foods and nutraceuticals.</p>