Isacio Calleja García (6 December 1936 – 4 February 2019) was a Spanish professional footballer who played as a defender.

[1] Save for a very brief loan spell with CD Guadalajara in the Tercera División he spent his entire 14-year professional career with Atlético Madrid, making his La Liga debut on 4 January 1959 in a 1–0 away loss against Real Oviedo and finishing his first season with only nine games (albeit all complete).

[1] From there onwards, Calleja became an important defensive member for the Colchoneros, helping the team to back-to-back Copa del Rey trophies from 1959 to 1961, both won against Real Madrid at the Santiago Bernabéu Stadium.

[2] On 19 April 1970, Calleja scored his only goal of the campaign in a 2–0 win at CE Sabadell FC, which granted Atlético the national championship.

He made his debut on 19 April 1961, in a 2–1 victory in Wales for the 1962 FIFA World Cup qualifiers.