Guido Petti Pagadizábal (born 17 November 1994) is an Argentine professional rugby union player who plays as a lock for Top 14 club Bordeaux Bègles and the Argentina national team.

[5] Guido played with San Isidro Club in the Torneo de la URBA in his homeland.

[5] Petti was a member of the Argentina Under-20 side which competed in the 2013 and 2014 IRB Junior World Championships, he also represented the Argentina Jaguars side in 2013 and 2014 and played for the Pampas XV during their 2014 tour of Oceania.

[2] He made his senior debut for Los Pumas on 14 November 2014 in a 20–18 victory over Italy in Genoa.

[8] Petti was a starter for the Argentina national team on 14 November 2020 in their first ever win against the All Blacks.