Dominion Voting Systems, an election technology company that became a target of a baseless pro-Trump conspiracy theory about rigged voting machines, sued the right-wing television networks Newsmax and One America News on Tuesday, accusing them of defamation.

Dominion, which also sued Fox News earlier this year, argued in the filings that both channels served as platforms for flagrant falsehoods that devastated its reputation.

“The defendants named show no remorse, nor any sign they intend to stop spreading disinformation,” Dominion’s chief executive, John Poulos, said in a statement. “We have no choice but to seek to hold those responsible to account.”

Dominion is seeking $1.6 billion in damages from each network. The company also sued Patrick Byrne, the former chief executive of Overstock.com who has publicly accused Dominion of rigging votes to ensure that President Donald J. Trump would not be re-elected. Mr. Byrne also falsely portrayed Dominion as linked to Hugo Chávez, the long-dead Venezuelan president.

Dominion had previously sued Mr. Trump’s lawyers, Rudolph Giuliani and Sidney Powell, for defamation, along with Mike Lindell, the chief executive of MyPillow and another Trump partisan who has relentlessly spread conspiracy theories about the 2020 election. Fox News has filed a motion to dismiss the Dominion suit.

Newsmax, which is owned by Christopher Ruddy, a Trump confidant, responded in a statement on Tuesday: “Newsmax simply reported on allegations made by well-known public figures, including the president, his advisers and members of Congress. Dominion’s action today is a clear attempt to squelch such reporting and undermine a free press.”

Representatives for One America News did not immediately respond to a request for comment.