Hydrogen production plants, either centralized or decentralized, do not always exist at the demand sites, making demand and supply asynchronous for various applications. Therefore, hydrogen storage becomes an inevitable part of hydrogen ecosystem. This chapter discusses the need for hydrogen storage for stationary and onboard applications and challenges that arise due to hydrogen's low density and high diffusivity. Different storage methods, such as compressed state hydrogen, liquid state hydrogen, physical storage through adsorption, and chemical storage methods, are discussed. Fundamentals of hydrogen gas, including the hydrogen phase diagram, ortho and para spin, and compressibility, are discussed to supplement the understanding of storage methods. Overall, this chapter highlights the need for hydrogen storage and specific targets by the US Department of Energy for the development of hydrogen energy-based vehicles.