Gels are captivating materials that, though often overlooked, are essential to our daily lives. They play a vital role in advanced sectors including food, soft electronics, e-mobility, pharmaceuticals, medicine, and cosmetics. Anisometric cellulose nanoparticles differing in morphology, crystallinity, and electrical surface charge can be prepared by bottom-up and top-down processes. These nanoparticles can self-assemble in aqueous dispersions to form nematic or cholesteric liquid-crystalline structures, facilitating sophisticated analytical and stimuli-responsive applications. This chapter provides an overview of the emerging field of nanocellulose hydrogels. It discusses both bottom-up and top-down production methods, explores various gel architectures, and examines opportunities for crosslinking and modification. Furthermore, it highlights the extensive range of applications for these materials, which extend beyond traditional hydrogels to include nanocellulose aerogels and carbon aerogels. Their biocompatibility and favorable rheological, mechanical, and chemical properties render them attractive for bio-inks and tissue engineering.