Lucas Ezequiel Viatri (Spanish pronunciation: [ˈlukas ˈβjatɾi];^{[lower-alpha 1]} born 29 March 1987) is an Argentine footballer who last played as a striker for Peñarol. He was capped three times for Argentina.

Viatri started his playing career with loan spells with Emelec of Ecuador and Unión Atlético Maracaibo of Venezuela. He returned to Boca Juniors in 2008.

On 17 May 2008, Viatri made his debut with Boca in a game 2–1 victory over Racing Club. In August 2008 he was part of the squad that won the 2008 Recopa Sudamericana. Subsequently, during the Apertura 2008 he was a regular on the first team and helped them get the championship title by scoring 8 goals, one of them at the Superclásico.

On 2 July 2014, Viatri transferred to Chinese Super League side Shanghai Shenhua.^[2] On July 15, 2014, Viatri made his debut with Shanghai Shenhua in a China FA Cup game against Chongqing Lifan, he scored twice and made an assist to help the super league side won 3–0. Six days later, Viatri scored twice again to let Shenhua won 3–2 against Liaoning Whowin in a Chinese Super League game.

On 11 August 2017 Lucas was acquired by Peñarol.

In 2008, before his Boca Juniors debut, Viatri was detained for 30 days, accused of committing an armed robbery to a hairdressing salon.^[5][6][7] Viatri was processed and subject to an oral proceeding. In the proceeding, the footballer agreed to a probation, and therefore was never sentenced guilty for the crime.

In 2009, the court that dealt with his case sentenced that he could not move outside Argentina before his probation finished, therefore thwarting his possibilities of transferring outside the country.^[8]

Boca Juniors

• Primera División: 2008 Apertura, 2011 Apertura
• Copa Argentina: 2011–12
• Recopa Sudamericana: 2008

Peñarol

• Uruguayan Primera División: 2017, 2018
• Supercopa Uruguaya: 2018