The effect of a series of ionic liquids on the regioselectivity of the azide-alkyne cycloaddition process was investigated, demonstrating an increased selectivity for the least hindered triazole. The effects of an ionic liquid on the activation parameters for the process were determined and found to be intermediate between coordinating and non-coordinating salts. The importance of knowing the water content of the system is demonstrated by marked changes in the activation parameters in the presence of small concentrations of water.