Medwin also represented Wales in the 1958 FIFA World Cup, scoring the game-winning goal in the first round play-off which sent Wales to the quarter-finals. He was the last player to score for Wales in the finals of a major tournament, until Gareth Bale scored in Wales' opening game of UEFA Euro 2016. In total he earned 30 caps and scored 6 goals for Wales from 1953 to 1963.