Publisher Summary This chapter summarizes the most important aspects of the synthesis and the application of organoclays. These include intercalation, grafting, and in situ incorporation of the organic moieties. This new class of porous solids attracted the attention of researchers in recent years with their unique properties and potential areas of application, which are beyond those of conventional layered type materials. Smectites, a subgroup of the phyllosilicates, attracted plenty of interest due to their swelling properties. Other subgroups include micas, kaolins, vermiculites, chlorites, talc, and pyrophyllite. These minerals are characterized by a 2:1 layer structure in which two tetrahedral sheets are attached on each side of an octahedral sheet via sharing of apical oxygens. The research effort is aimed at developing of synthesis methods to better control the physicochemical characteristics of organoclays. The synthesis of covalently linked inorganic–organic lamellar composites with ion exchange properties and tailored hydrophobicity were carried out using a single-step templating sol–gel procedure. The syntheses involved reaction of magnesium nitrate and aluminum acetylacetonate with octyltriethoxysilane. The applications vary from heavy metal remediation and catalysis to adsorption of organic pollutants and immobilization of biomolecules. The organoclays are also considered as promising materials as environmental barriers, polymer fillers, catalytic supports, chemical sensors, and porous vehicles for chemotherapy drugs.