Steven Diez (Spanish: Díez, pronounced ; born March 17, 1991) is a Canadian and former Spanish professional tennis player. Raised primarily in and competing for Spain early in his career, he has since gone on to represent the country of his birth, Canada, in the Davis Cup.
Diez competed in the main draw of two senior level ITF Futures tournaments in the autumn, losing both times in the first round. In his first match, at Spain F39 in late October, he fell to world No. 422 Carles Poch-Gradin. He fared much better a month later taking a set off world No. 425 Juan Albert Viloca-Puig before losing.
Diez won his first tour match in his third tournament of the year, Spain F11. He won his first ever doubles match too, partnering Ignacio Morente-Gemas to the second round of Spain F13. He then won two matches partnering Javier Valenzuela-Gonzalez to reach the semi-finals of Spain F14. The same pairing reached the semis in their next tournament too, in July, at Spain F26.