Extracts of algae and their products are the components of cosmetics or cosmeceuticals. The active ingredients extracted from algal biomass can be used in three ways: as additives; as stabilization and preservation of the product; and as the compounds that fulfil a real cosmetic function and activity. The most frequently used extracts in cosmetic formulations are derived from: brown macroalgae, green macroalgae, and red macroalgae. Microalgae can be cultivated in artificial batches, fed‐batches and continuous modes. Nowadays, biotechnology techniques enable the production of high‐quality algal cultures that are free of contaminants which is necessary in the cosmetic industry. This chapter presents biologically active compounds extracted from algae that can play a key role in cosmetic products. It describes some of the examples of their action on the skin. The chapter includes anti‐aging care, anti‐photoaging care, antioxidant and photoprotection, moisturizing and smoothing, whitening, and anti‐cellulite and slimming care.