Nanoscience and nanotechnology mainly deal with the synthesis, characterization, study of nanostructured materials, and their applications. The properties (physical and chemical) of the nanomaterials differ significantly with their synthesis methods. Synthesis and processing of nanostructured materials is an important aspect of nanotechnology. The exploration of new physical properties and applications of nanomaterials is possible when nanostructured materials are made with controlled size, morphology, crystallinity, and microstructure, and desired chemical composition. The top-down and bottom-up approaches are well-known for the synthesis of nanomaterials. The wet chemical synthesis of nanomaterials is included in the bottom-up approach that refers to the build-up of a material from the smallest size, i.e., atom by atom, molecule by molecule. Various kinds of wet chemical methods such as sol-gel, chemical precipitation, hydrothermal-solvothermal synthesis, polyol synthesis, micro-emulsion, sonochemical, and spray pyrolysis, etc. promise a better control over size and properties of the nanomaterials, and produce homogeneous chemical composition with narrow size distribution. This chapter introduces the importance and effectiveness of wet chemical synthesis methods in producing nanomaterials with better size and properties for various technological applications.