The Baltimore-based sports apparel company has supplied uniforms for other colleges including Northwestern University and the University of Maryland, but the Notre Dame deal represents its most high-profile college sports contract to date.
ESPN reported that the terms of the deal, which is expected to be signed soon, are not known. But the sports network said the Under Armour contract would start in the next school year, replacing Adidas.
ESPN sources said Under Armour CEO Kevin Plank flew to South Bend, Ind., on Thursday to meet with school officials.
A spokesman for the University of Notre Dame said nothing was official yet. Representatives from Under Armour did not immediately respond to requests for comment.
Under Armour is known for technological advances in uniforms as well flashy designs.
The University of Maryland caused some social media snickers in 2011 with the state flag inspired "Maryland Pride" uniforms. They were later updated with a more toned-down design.
Last year, the company sparked a minor controversy when some said its American flag themed uniforms for the Northwestern football team looked as if they were stained with blood. Under Armour said the stains were meant to convey a distressed look of a flag that had been flown over a long period of time.