The International Union of Pure and Applied Chemistry (IUPAC) classifies porous materials into three categories according to their pore sizes: microporous (<2 nm), mesoporous (2–50 nm), and macroporous (>50 nm). Since the exciting discovery of ordered mesoporous silicates in the 1990s (MCM-41, SBA-15, etc.), functional mesoporous materials have attracted increasing interest owing to their fascinating properties such as tunable large pore sizes, high surface areas, large pore volumes, alternative mesostructures, as well as their wide range of promising applications in catalysis, adsorption, separation, sensors, water treatment, energy conversion and storage, biomedicine, and nanodevices. In the past three decades, the family of functional mesoporous materials has expanded to include a wide range of compositions, such as silica, carbon/polymer, metal, metal oxide, and organic–inorganic hybrid. With the development of nanotechnology, tremendous progress has also been made in the synthesis of nanosized mesoporous materials with a variety of morphologies, such as nanofibers, nanorods, nanosheets, core@shell nanoparticles, and asymmetric nanocomposites.