A Clinton campaign spokesman has rejected the accusations.
The wrongful death lawsuit, filed in federal court in Washington, attempts to tie Clinton’s use of a private email server while secretary of state to the deaths of four Americans, including ambassador Chris Stevens, in the attacks on September 11, 2012.
The plaintiffs are Pat Smith of San Diego and Charles Woods of Portland, Oregon. Their sons, state department employee Sean Smith and security contractor Tyrone Woods respectively, were among those killed in the Libyan attack.
“As a direct result of defendant Clinton’s reckless handling of this classified, sensitive information, Islamic terrorists were able to obtain the whereabouts of ambassador Christopher Stevens and thus the US state department and covert and other government operations in Benghazi, Libya, and subsequently orchestrate, plan, and execute the now infamous September 11, 2012 attack,” states the lawsuit.
Mr Smith and Mr Woods are also suing Clinton for defamation over public statements in which she denied telling the parents that the attacks were prompted by an anti-Muslim video on YouTube.
Clinton campaign spokesman Nick Merrill said the Benghazi attacks have been exhaustively investigated.
“While no one can imagine the pain of the families of the brave Americans we lost at Benghazi, there have been nine different investigations into this attack and none found any evidence whatsoever of any wrongdoing on the part of Hillary Clinton,” said Mr Merrill.
A special committee set up by House Republicans blamed the Obama administration for loose security in Benghazi, but did not level direct accusations of wrongdoing at Clinton personally.