A classical fullerene is composed of hexagons and pentagons only, and its stability is generally determined by the Isolated-Pentagon-Rule (IPR). In 2005 Taylor et al. reported the first cage skeletal transformation of fullerene C₆₀ via fluorination at 550 ⁰C, affording two stable non-classical fullerene derivatives containing heptagons. It is then intriguing to investigate whether cage skeletal transformation of fullerene can be fulfilled under less harsh conditions. Herein, we present our recent studies on cage skeletal transformations of classical higher fullerenes in the course of high-temperature chlorination. Chlorination-promoted cage skeletal transformations occur by Stone-Wales rearrangements (SWRs, i.e., a rotation of a C−C bond by ca. 90°) and/or losses of C2 units (C2Ls). In particular, the C2L realized by the removal of a 5:6 C-C bond from the cage generates a cage heptagon, thus resulting in the formation of a non-classical cage. We show several examples of chlorination-promoted one-, two-, and multi-step cage transformations in different higher fullerenes.