The Euskadiko Sozialisten Batasuna (English: Basque Socialist Union, ESBA) was a clandestine political movement in the Southern Basque Country, Spain, formed in 1959, and active under Francoist Spain.
In 1962 several militants of ESBA were arrested in Donostia, including their leader José Ramón Recalde.
In 1965 Recalde was jailed again for refusing to pay a fine imposed for denouncing torture.
[citation needed] The group disappeared in 1969, due to police repression and to internal contradictions.
Some former leaders of ESBA participated in the VI Assembly of ETA (1970), when most delegates approved an approach to revolutionary Marxism and the abandonment of the traditional nationalist thesis, splitting and creating the Liga Komunista Iraultzailea-ETA VI Assembly (LKI-ETA VI).