A method of producing an ethylene-vinyl alcohol copolymer resin composition comprises feeding water-containing pellets of an ethylene-vinyl alcohol copolymer from 0°C to 80°C and an additive to an extruder (X) for melt kneading, wherein the additive includes at least one selected from the group consisting of carboxylic acid, a boron compound, a phosphoric acid compound, an alkali metal salt, and an alkaline earth metal salt, the additive is added to the ethylene-vinyl alcohol copolymer in the extruder (X), a melt in the extruder (X) has a temperature T 0 from 70°C to 180°C and the extruder (X) has a cylinder temperature T 1 from 65°C to 175°C, T 0 and T 1 satisfy an expression (1) below 5 ≤ T 0 -T 1 ≤ 100(1), and the water-containing pellets fed to the extruder (X) has a water content from 20 to 60 mass% and a water-containing resin composition immediately after extrusion from the extruder (X) has a water content from 10 to 35 mass%. The production method allows, in the method comprising melt kneading the water-containing ethylene-vinyl alcohol copolymer pellets and the minor component in the extruder, followed by extrusion, highly efficient dewatering of the water-containing ethylene-vinyl alcohol copolymer pellets and also causes the EVOH resin composition thus obtained that has less foam and has a good hue.