In the recent two decades, there has been a tremendous increase in the biosynthesis of nanomaterials employing live organisms, their components, extracts, or biomolecules as catalysts. Algae has been used majorly for commercial and industrial uses such as food, feed, skin care, medicines, and fertilizers, algae are now being explored to synthesize green nanoparticles (NPs). Indeed, algae are a rich source of bioactive substances, are easy to produce, grow quickly, and are scalable, therefore this trend is growing by the day. The natural material from algae works as a capping and stabilizing factor in the conversion of metal compounds to metal, metal oxides, or bimetallic NPs. The NPs generated by algae might be intracellular or extracellular, depending on the area of the NPs. The aim of the present review, the first of its kind, is to provide readers with essential information about the diversity of algal strains exploited in the booming field of nanobiotechnology and to explore the biomedical applications of NPs biosynthesized from algae which include antimicrobial, antioxidant, anticancer and biocompatibility properties. Furthermore, this study examines the rationale for the algal-mediated creation of metal, metal oxide, and bimetallic NPs from a variety of algae, as well as the characterization of algae-mediated nanomaterial synthesis.