Óscar Javier González Marcos, simply Óscar, is a Spanish professional footballer who plays for Real Valladolid as a midfielder.

Óscar began his career with Real Valladolid, making his first team – and La Liga – debut in the 1–0 home win over UD Las Palmas, on 7 October 2001. Establishing himself as a regular by the start of the 2002–03 season, he was the side's best scorer in the following year at 10, in spite of a final relegation.

Subsequently, Óscar moved to Real Zaragoza, where he was a regular fixture throughout four seasons, whether as a starter or a substitute. His best scoring output came during his first season, with six goals (two being in a 2–2 draw at CA Osasuna).

After Zaragoza's relegation in 2007–08, he joined Olympiacos F.C. on a three-year deal during the summer transfer season, joining countryman Ernesto Valverde's roster. During his two-year spell, he played in a total of 68 games, scoring nine times, but his performances were irregular. Helping to the PIraeus club double in his first season, he also scored in the 2008–09 UEFA Cup, in a 1–2 loss at AS Saint-Étienne (2–5 on aggregate) for the round of 32.

On 1 September 2010, Olympiacos parted ways with Óscar, whom immediately signed with his first professional club, Valladolid, now in the second division.