Mason A. Diaz (born May 16, 2000) is an American professional stock car racing driver.

[1] Diaz made his first and to-date only NASCAR Camping World Truck Series start in 2017 at Martinsville, driving the No.

[2][3] Diaz made his Xfinity Series debut at Richmond's fall race in 2018, driving for Brandonbilt Motorsports in the No.

20 Toyota in the ARCA Menards Series in the races that Chandler Smith was ineligible to drive in.

[5] On January 19, 2021, it was announced that Diaz would be leaving Venturini and joining Visconti Motorsports, driving their No.