The participation of Spain in the Junior Eurovision Song Contest first began at the inaugural Junior Eurovision Song Contest in 2003 which took place in Copenhagen, Denmark. Televisión Española (TVE), a division of Radiotelevisión Española (RTVE) and member of the European Broadcasting Union (EBU), were responsible for the selection process of their participation. Spain used a national selection format, broadcasting a show entitled Eurojunior, for their participation at the contests. The first representative to participate for the nation at the 2003 contest was Sergio with the song "Desde el cielo", which finished in second place out of sixteen participating entries, achieving a score of 125 points. Spain did not participate from 2007 to 2018, but returned to the contest in 2019.

The Junior Eurovision Song Contest is an international song competition which has been organised by the European Broadcasting Union (EBU) annually since 2003.