The inclusion reactions of some azo guest molecules, 3’-Pr-4’-(OH)Ph-N=N-PhSO(3)(-)Na(+) (1), 3’-iPr-4’-(OH)Ph-N=N-PhSO(3)(-)Na(+) (2), and 3’-tBu-4’-(OH)Ph-N=N-PhSO(3)(-)Na(+) (3), with hexakis(2,6-di-O-methyl)-alpha-cyclodextrin (DM-alpha CDx) were investigated. The rates and mechanism for the inclusion reactions of 1, 2, and 3 with DM-alpha CDx have been determined. Enhanced binding ability with the guest and a three-step inclusion mechanism by DM-alpha CDx were found.