A host of the MTV show “Catfish,” Nev Schulman, has been accused of sexual misconduct and suspended, days after a woman posted videos online strongly intimating that he sexually harassed her during shooting of the program in 2015.

“Catfish” follows people who fall for each other online yet often lie about who they are, and grew out of a 2010 documentary in which Mr. Schulman got duped over Facebook by a woman who used someone else’s picture and a fake name.

Hosted by Max Joseph and Mr. Schulman, who also serves as an executive producer, the show’s seventh season ended in March, but future production is now on hiatus pending the outcome of an internal investigation into Mr. Schulman. “We take these allegations very seriously,” the network said in a statement issued Thursday.

While neither MTV nor the show’s production company, Critical Content, would comment on the nature of the claims, the suspension came less than a week after Ayissha Morgan, a guest during Season 4, posted two YouTube videos saying “the main person” on the show, whom she called “Jack,” apparently as a pseudonym, repeatedly harassed her during production.