Nikola, which was founded in 2014, first unveiled the design for its electric semi truck in May 2016. The company said Tesla tried to poach the company's chief engineer a few months later.
Ahead of Tesla's reveal of its own semi truck a year and a half later in November 2017, Nikola sent a cease-and-desist letter asking the company to delay its unveiling until patent issues were resolved.
Tesla denied it has done anything wrong.
"It's patently obvious there is no merit to this lawsuit," Tesla told The Verge.
Nikola's spokesperson told TheStreet that the company's lawsuit speaks for itself and that "Nikola is defending its intellectual property."
Tesla had not disclosed that it was considering building a semi-truck until after seeing the designs Nikola posted on its website on May 9, 2016, according to the lawsuit.
Tesla ended up announcing its own semi truck plans on July 20, 2016, with a blog post saying that the company was "in the early stages of development at Tesla and should be ready for unveiling next year."
Tesla unveiled the vehicle in November the next year.
Nikola claims that Tesla did not have any design patents on its semi as of April 28, 2017, nearly a year after Nikola had unveiled its design.
Tesla still does not have any design patents on the truck, according to Nikola, meanwhile, the U.S. Patent office has issued six design patents to Nikola between February and April 2018.