Vapour phase aniline alkylation is carried out over montmorillonite K10, vanadia modified montmorillonite K10, silica and vanadia modified silica. Montmorillonite K10 proved to be a better catalyst for aniline alkylation than silica. However, vanadia impregnation enhanced the alkylation ability of the latter making it as good a catalyst as vanadia impregnated montmorillonite K10. The catalyst systems are compared from the point of view of vanadia dispersion and vanadia-support interaction, The catalysts are characterised by BET surface area, XRD, ESR and by acidity measurements. Acidity measurement by step wise temperature programmed desorption of ammonia using a Micromeritics pulse chemisorb 2700 unit is described. Aniline alkylation ability of the catalysts is discussed with respect to catalytic acidity.