The living isobutylene oligomerization initiated by diisobutylene hydrochloride (1) or triisobutylene hydrochloride (2) in the presence of BCl3 and benzyltriethylammonium tetrachloroborate has been studied by gas chromatography which allowed the detection of the individual oligomers 2, 3, 4, etc. The reactions followed second-order kinetics, first-order with respect to initiator (1 or 2), first-order with respect to BCl3, and zeroth-order with respect to isobutylene. A kinetic model has been derived which explains these phenomena.