Hydroxyselenation of terminal or cyclic allylic alcohols occurs with high regio- and stereoselectivity to give β,β′-dihydroxyphenylselenated adducts in high yields. A mechanism for this selectivity is proposed. The utility of these adducts is illustrated by the conversion of the hydroxyselenide (9a) to the epoxide (11) via the intermediacy of a selenone.