Most applications of mesoporous silica require some degree of functionalization. The surface of porous materials can be divided into external and internal (pore) surfaces, and in many cases, a selective functionalization of these surface subsections is desired. This short review outlines our recent work in this field and focuses on the postsynthetic functionalization of mesoporous silica with aminopropylalkoxysilanes and on the analysis of the respective functional group distributions by confocal laser scanning microscopy. Methods to obtain an amino-functionalized external surface and functional group gradients on the pore surface are reported. Arrays of silica nanochannels (ASNCs) serve as a model system for mesoporous silica.