Tomás Vallejos Cinalli (born 16 October 1984) is an Argentine rugby union player.

A lock forward, Vallejos started his career at Logaritmo Rugby Club in Rosario, before moving to Italy to play professionally for Overmach Parma.

Vallejos signed for English side Harlequins during the 2009–10 season to fill the gap left by the injured Jim Evans.

[3] He was granted a release from his contract with Scarlets to allow him join the Pampas XV and compete fully in the 2013 Vodacom Cup.

[4] Vallejos has represented Argentina in the U17, U18, U20 and U23 age groups, and won his first senior cap as a replacement at the 2011 Rugby World Cup against Georgia.