The field of nanotechnology has shown great promise in various industries due to its versatile applications. Phyconanoparticles derived from algae, which come from different algal groups like Bacillariophyta, Chlorophyta, and Charophyta, are becoming more well-known due to their unique characteristics and eco-friendly production methods. Several algal strains are used in the synthesis of Phyconanoparticles, and each one adds unique biochemical components that have a substantial influence on the physical and chemical attributes of the finished nanoparticles. This technique often involves the reduction of ambient metal ions, which results in the controlled production of nanoparticles. This multidisciplinary method uses the unique properties of algae to create environment-friendly metallic nanoparticles and has been appropriately named “phyconanotechnology.” Further investigation is required to comprehend the complex mechanisms underlying the synthesis of algal nanoparticles. To fully comprehend the reaction mechanisms, it is imperative to acknowledge the proteins and enzymes causing this process. This chapter delves into the various algae forms used to prepare nanoparticles and examines their distinct characteristics. It also describes the different processes and techniques used to synthesize phyconanoparticles. Furthermore, it examines the diverse industries in which phyconanoparticles are employed and makes predictions regarding the potential of phyconanotechnology in the future. The objective of this chapter is to present a comprehensive outline of the situation of this field’s research and encourage additional investigation into the possibilities of algal-based nanotechnology.