Dislocations of the interphalangeal joint of the great toe that are irreducible are very rare. Invagination of the plantar plate or the sesamoid bone into the IP joint, which prevents reduction. To our knowledge, however, dislocations of the IP joint of the great toe that were irreducible because of lateral collateral ligament entrapment, not invagination of the plantar plate or the sesamoid bone, have not been reported by any English literature. We report a 29-year-old ballet dancer who sustained an irreducible dislocation of the interphalangeal joint of the great toe owing to lateral collateral ligament entrapment.