Pablo César Aimar (born 3 November 1979) is an Argentine former professional footballer and current assistant coach of the Argentina national team. During his career, he played as an attacking midfielder.

After starting his senior career at River Plate in 1996, Aimar amassed La Liga totals of 215 games and 32 goals over eight seasons with Valencia and Zaragoza from 2001 to 2008, before spending five years in Portugal with Benfica, winning a combined nine major titles with the three teams.

Aimar earned 52 caps for the Argentina senior team over ten years, representing the nation in two FIFA World Cups and two Copa América tournaments, as well as a FIFA Confederations Cup. He reached the final of the 2005 Confederations Cup and the 2007 Copa América with the Argentine national side.

In 2018, Aimar joined the Argentina national team as an assistant coach. During his tenure, the team won the 2021 Copa América, the 2022 Finalissima, the 2022 World Cup, and the 2024 Copa América.

Aimar's football career begun in earnest when he was offered the chance to play for Estudiantes de Río Cuarto by youth coach Alfie Mercado. He trained with the club's academy three times a week and it was there that he was spotted by River Plate who offered the chance to join their own academy. Aimar's father initially prevented him from joining River as he felt he was too young to be playing football, but relented after manager Daniel Passarella personally asked him to allow his son to play. Having turned down the opportunity to attend medical school to pursue a career in football, Aimar made his debut for River on 11 August 1996 against Colón. His first goal for the club came on 20 February 1998 against Rosario Central. Aimar lifted five titles with River between 1996 and 2000, scoring 21 goals and recording 28 assists in 82 league appearances for the club, with his final appearance coming on 17 December 2000 in a 3–2 loss to Lanús.

In January 2001, Spanish La Liga side Valencia signed Aimar from River for a club-record fee of €24 million (£13 million). He made his debut for the club the following month against Manchester United and drew praise from three-time Ballon d'Or winner Johan Cruyff for his performance after the match. The following weekend he scored on his La Liga debut, netting in a 2–0 away win over Las Palmas. Aimar immediately became a key figure in Valencia's midfield under Héctor Cúper and helped the club reach the 2001 UEFA Champions League final, where they lost to Bayern Munich on penalties.

In the season which followed, Cúper left for Internazionale, and was replaced by Rafael Benítez. Aimar appeared in a total of 33 league games and scored 4 goals as Valencia were crowned 2001–02 La Liga champions for the first time in 31 years, ending as the club's third-highest goalscorer across all competitions for the season. The season thereafter, Aimar jointly topped the Champions League assists table alongside Rui Costa of Milan with five assists to his name, this despite Valencia being eliminated at the quarter-final stage. The club endured further disappointment by ending the league season in fifth place.

"Pablo is the only current footballer I'd pay to watch. He’s been the best player in Argentina over the last couple of years and is even more talented than Riquelme or Saviola.