The MLW National Openweight Championship is an openweight professional wrestling championship created and promoted by the American professional wrestling promotion Major League Wrestling (MLW). The title was unveiled on April 18, 2019. The title's openweight nature means that wrestlers from both MLW's heavyweight and middleweight divisions are eligible to challenge for it.

On April 18, 2019, Major League Wrestling (MLW) announced the creation of the MLW National Openweight Championship, a secondary championship for the company to be defended in their newly created openweight division, a division more common in Japanese professional wrestling. Also announced was a four-man single-elimination tournament that would culminate on June 1 with the crowning of the first champion. The tournament to crown the inaugural champion was later advertised on MLW Fusion, while being announced four wrestler to participate in the tournament, which was announced on May 4 by MLW Fusion's Executive Producer Salina de la Renta. The title was unveiled on May 17. On June 1 at Fury Road, Alexander Hammerstone defeated Brian Pillman Jr. in the finals of the tournament to become the inaugural MLW National Openweight Champion.

As of November 19, 2025, there have been nine reigns between nine champions and one vacancy. Alexander Hammerstone was the inaugural champion. Hammerstone's reign is the longest at 865 days, while John Hennigan's reign is the shortest at 89 days. Hennigan was also the oldest champion when he won it at 43 years old, while Alex Kane was the youngest champion at 28 years old.

Último Guerrero is the current champion in his first reign. He defeated Matthew Justice at CMLL vs. MLW on May 2, 2025 in Mexico City, Mexico.