Silica has many applications in various sectors such as construction, the chemical industry, agriculture, health care, environment remediation, etc. It is currently being synthesized from inorganic precursors that are indirectly prepared from quartz sand, the second most used nonrenewable resource. Due to environmental hazards associated with the current synthesis process and health hazards associated with inorganic precursors, there is an urgent need for alternative sources for the synthesis of silica and silica-based materials. Agriculture waste biomass which is otherwise mostly a menace to the environment can be a much greener alternative in this scenario. This chapter discussed in detail various approaches (viz. thermal, chemical, and biological) used to obtain silica from agriculture waste biomass with several reports from the literature. It includes examples of the synthesis of various silica materials from agriculture waste materials such as rice husk, rice straw, bagasse, bamboo leaves, etc., and their properties. Several cases of applications of bio-derived silica in various fields and recent pilot scale studies are also discussed at the end.