Allenylsilanes undergo enantioselective intramolecular photocycloaddition reactions with enones and enoates to give adducts in 76-99% enantiomeric excess and 67-90% yield. The silyl-substituted exo-methylenecyclobutane products undergo protodesilylation to give the parent unsubstituted exo-methylenecyclobutane. Optically active allenylsilanes may thus be used in enantioselective photocycloadditions in which the silyl moiety functions as a removable stereochemical controlling group.