A composition containing an ethylene-vinyl alcohol copolymer (A), a zinc oxide (B), and a zinc salt (C) other than the zinc oxide (B), the zinc salt (C) being an inorganic zinc salt and/or an organic zinc salt having from 1 to 6 carbon atoms, and a mass ratio [(C)/(B)] of a content of the zinc salt (C) in terms of metal to a content of the zinc oxide (B) in terms of metal being more than 0.5 is provided as a composition having excellent gas barrier properties, especially excellent oxygen barrier properties, at high humidity.