Paradoxical patterns of pupillary, lid and eye movement may follow oculomotor nerve palsy or they can develop spontaneously in patients with no known history of oculomotor palsy. The mechanism of this condition, known variously as aberrant regeneration of the third nerve, oculomotor misdirection or acquired oculomotor synkinesis, is not known, although the prevailing opinion has held that it occurs when axons regenerating within an oculomotor nerve become misdirected and innervate muscles for which they were not intended. However, there is evidence against this hypothesis. The authors critically review the various hypotheses and elucidate the controversy concerning the pathogenesis of acquired oculomotor synkinesis.