Julen Guerrero López (born 7 January 1974) is a Spanish former professional footballer who played solely for Athletic Bilbao as an attacking midfielder.

Born in Portugalete, Biscay, Guerrero joined Athletic Bilbao as an eight-year-old,[4][5][6] and subsequently progressed through the junior ranks of the club.

Along with Aitor Karanka, he was a member of the under-19 team that won a national double of cup and league in 1991–92, and also appeared and scored for the reserves in the Segunda División during the same season.

[17][18][19][5][8] In 1997–98, Guerrero netted eight times in 29 matches as the Basques finished second, leading to direct qualification for the UEFA Champions League where he put on strong performances in the group stage against Juventus and Galatasaray.

[20] Subsequently, however, his career went into decline and, in 2002, he was deemed surplus to requirements by coach Luis Fernández while still only 28;[4][8] in his last four seasons he could only manage 57 games with just four goals but, despite his poor form, remained a fan favourite,[2] and the decision to drop him caused some controversy.

[31] Often hailed as one of the greatest attacking midfielders of his generation,[32][4] Guerrero was ambidextrous, and was renowned for his free kicks and finishing skills, derived from his sharp nose for goals.