Mesoporous materials have many present and potential future applications for catalysis, chemical and biological separations, chromatography, photonic and electronic devices, drug delivery, and energy storage. [1] They are typically synthesized with amphiphilic organic molecules as templates through the cooperative assembly between these molecules and inorganic species. Since their discovery, control of ordered mesoporous structures and pore sizes has been widely investigated by changing synthetic conditions and by using different types of amphiphiles, including small charged surfactant molecules and large block copolymers. Meanwhile, progress has also been made in the assembly of surfactant molecules and inorganic species into mesoporous materials with a wealth of morphological shapes and internal pore architectures, such as spheres, [2] gyroids, [3] fibers, [4][5][6] tubules, [7] and thin films, [8] for a variety of applications. Furthermore, cooperative assembly between inorganic and organic components has recently become an exciting approach for the development of novel multifunctional materials. [9] Ribbon-shaped one-dimensional nanostructures made of transition metals, [10] transition metal oxides, [11] and II-VI semiconductor compounds [12] have been extensively investigated owing to their distinctive geometries, novel physical and chemical properties, and potential applications in magnetic, electronic, and photonic devices. These inorganic ribbons are prepared by using either a vapor-solid or a solution-solid process. They exhibit the same crystallographic structures as the corresponding bulk materials and are usually enclosed by low-index facets with rectangular cross sections. Here, we report the synthesis of single-crystal mesoporous silica ribbons by using small cationic surfactant molecules. These ribbons have tracklike pore channels that are oriented perpendicular to the length of the ribbon and are hexagonally