The present invention provides a resin composition containing: (A) an ethylene-vinyl alcohol copolymer having an ethylene content of 20 mol % or more and 50 mol % or less; (B) an ethylene-vinyl alcohol copolymer having an ethylene content of 30 mol % or more and 60 mol % or less; and (C) an unsaturated aldehyde, a value obtained by subtracting the ethylene content of the ethylene-vinyl alcohol copolymer (A) from the ethylene content of the ethylene-vinyl alcohol copolymer (B) being 8 mol % or more, a mass ratio (A/B) of the ethylene-vinyl alcohol copolymer (A) to the ethylene-vinyl alcohol copolymer (B) being 60/40 or more and 95/5 or less, and the content of the unsaturated aldehyde (C) with respect to a resin content being 0.01 ppm or more and less than 100 ppm.