José Gabriel Sagastume Ríos (born January 5, 1982, in Guatemala City) is a Guatemalan taekwondo practitioner, who competed in the men's featherweight category.

Sagastume made his official debut, as an 18-year-old teen, at the 2000 Summer Olympics in Sydney, where he lost his opening match to Filipino taekwondo jin Roberto Cruz in the men's flyweight class (58 kg).

[2][3] At the 2004 Summer Olympics in Athens, Sagastume qualified for the Guatemalan squad in the men's featherweight class (68 kg), by placing third and granting a berth from the Pan American Olympic Qualifying Tournament in Querétaro, Mexico.

[4][5] Sagastume improved his previous Olympic feat by dispatching South Africa's Duncan Mahlangu (11–7) in the prelims and Australia's Carlo Massimino (5–4) in the quarterfinals, before falling in a defeat to Chinese Taipei's Huang Chih-hsiung, who landed him a counterblow by a late surge to produce a 7–5 record.

[6] In the repechage rounds, Sagastume gave himself a chance to campaign for his nation's first Olympic medal, but he was cautiously beaten by Brazil's Diogo Silva with a score of 10–12.