The air oxidation of tetrakis(2,4,6-triisopropylphenyl)disilene (1) has been investigated. In benzene solution the first oxidation product is the 1,2-disiladioxetane 2, which rearranges to give the 1,3-cyclodisiloxane 3 in addition to a compound with the 1-oxa-2-silacyclopent-3-ene structure (4). The same products are obtained when solid 1 is oxidized. Conditions for the rearrangement of 2 which provide either 3 or 4 pure are also described. Oxidation of 1 with 1 equiv of m-chloroperbenzoic acid produces the disilaoxirane 5 and, with excess oxidant, 3. The X-ray crystal structures of 3 and 5 are reported.