Gago was named in Argentina's 23-man squad for the 2014 FIFA World Cup. He made his World Cup debut in Argentina's 2–1 defeat of Bosnia and Herzegovina at the Estádio do Maracanã, coming on as a half-time substitute for Hugo Campagnaro. He was named in the starting line-up for the team's second match, a 1–0 win over Iran in Belo Horizonte, and remained a starter until being replaced by Lucas Biglia in the quarter-finals. Gago replaced Enzo Pérez after 86 minutes of the final, which Argentina lost 0–1 to Germany after extra time.