Elon Musk, the brash Silicon Valley billionaire, was sued on Monday by a British cave explorer he had accused of being a pedophile after the two butted heads over the high-profile rescue of children from a cave in Thailand this summer.

In the lawsuit, filed in United States District Court in California, lawyers for the caver, Vernon Unsworth, accused Mr. Musk of embarking on a defamation campaign “to destroy” Mr. Unsworth’s reputation “by publishing false and heinous accusations of criminality.”

“Musk’s influence and wealth cannot convert his lies into truth or protect him from accountability for his wrongdoing in a court of law,” one of the caver’s lawyers, L. Lin Wood, said in an emailed statement. The suit is seeking damages in excess of $75,000.

The lawsuit stems from the efforts to rescue members of a children’s soccer team who, with their coach, became trapped by rising waters in a Thai cave on June 23 — a predicament that captivated the world. According to the lawsuit, Mr. Unsworth, who had explored the cave over the past six years, got involved the next day.