Interlayer silylation of layered sodium octosilicate (Na-Oct) with various organoalkoxysilanes was conducted using hexadecyltrimethylammonium ion-exchanged layered octosilicate (C 16 TMA-Oct) as an intermediate in the presence or absence of tetrabutylammonium fluoride (TBAF). The degree of silylation was increased by adding TBAF. It is suggested that F À ions perform a nucleophilic attack on the alkoxysilanes, which promotes the silylation reaction. C 16 TMA-Oct was silylated with octyltriethoxysilane (C 8 TES) or 3-mercaptopropyltriethoxysilane (MPTES) to compare the reactivity of the two organoalkoxysilanes in the presence or absence of TBAF. A higher degree of silylation of C 16 TMA-Oct was observed with MPTES, suggesting the higher accessibility of this silylating agent into the interlayer polar region of C 16 TMA-Oct. Overall TBAF appears as a relevant catalyst for the covalent interlayer surface modification of layered silicates with organic functional groups.