Diego Lainez Leyva (born 9 June 2000) is a Mexican professional footballer who plays as a winger for Liga MX club Tigres UANL and the Mexico national team.

[3] On 1 March 2017, Lainez made his competitive debut with América in the Copa MX group stage match against Santos Laguna.

[5] On 19 March, after a lineup error that ruled out Gerson Torres from being eligible to play,[6] Lainez was assigned to start against Pumas UNAM.

[8] On 18 September, Lainez suffered a sprained ankle on his left foot during training following a tackle from Bruno Valdez,[9] forcing him to miss out on four weeks of action, including the Súper Clásico against arch-rivals Guadalajara.

[13] On 10 January 2019, Lainez joined La Liga club Real Betis on a five-year contract reportedly worth $14 million.

[19] On 14 February, he became the youngest Mexican player to score in the UEFA Europa League when he netted an injury-time equalizer in a 3–3 draw with Rennes in the first leg of the round of 32.

[20] On 19 December, Lainez scored his second competitive goal for Betis – a free kick – in the 4–0 victory over Antoniano in the first round of the Copa del Rey.

[40] On 29 August 2018, Lainez received his first call-up to the senior national team by interim manager Ricardo Ferretti for the friendly matches against Uruguay and the United States.

[43] On 6 June 2021, Lainez scored against the United States just seconds after coming on as a substitute in the CONCACAF Nations League Final to make it 2–1, but Mexico ultimately lost 3–2.

[56] Thomas Harrison of Outsideoftheboot.com described him as "a winger who can also operate as a 'number ten', [he] is renowned for his outstanding balance, trickery and change of pace when running with the ball, and the stats back up this belief.