WASHINGTON—Casino mogul Steve Wynn is stepping down from his post as Republican National Committee finance chairman, the committee said Saturday, following a Wall Street Journal report alleging a decadeslong pattern of sexual misconduct by him.
“Today I accepted Steve Wynn’s resignation as Republican National Committee finance chair,” said RNC Chairwoman Ronna Romney McDaniel.
The Wall Street Journal on Friday reported that shortly after Mr. Wynn opened his flagship Wynn Las Vegas in 2005, a manicurist who worked there told a colleague Mr. Wynn forced her to have sex. The casino billionaire later paid the manicurist a $7.5 million settlement, the Journal reported.
Beyond that incident, dozens of people the Journal interviewed who have worked at Mr. Wynn’s casinos described a pattern of sexual misconduct.
Mr. Wynn denied the accusations, saying, “The idea that I ever assaulted any woman is preposterous.” A spokesman for Mr. Wynn didn’t immediately return a request for comment on his resignation from the RNC.
President Donald Trump, who called Mr. Wynn a “great friend” in 2016, hasn’t commented on the allegations. On Friday evening, his Twitter account “liked” a Wall Street Journal tweet about the allegations. His account has since unliked the tweet.
In addition to heading the RNC’s fundraising operation, Mr. Wynn is a longtime Republican donor. In the 2016 campaign, he gave more than $160,000 to Senate Republicans’ campaign arm. He also gave more than $80,000 to the RNC, and gave another $70,000 in 2017.
Mr. Wynn hosted a Jan. 20 fundraiser at the president’s Florida resort, Mar-a-Lago, to benefit the RNC and Trump re-election campaign. The president appeared by video message after he canceled his visit because of the government shutdown.
Following allegations of sexual assault against longtime Democratic donor Harvey Weinstein last year, the RNC repeatedly pressured Democratic groups and candidates to return money from the donor, releasing a video calling for them to “put your money where your mouth is.”
RNC officials emailed members late Friday to add an item to the next meeting agenda: discussing the finance chairman position.
The GOP committee hasn’t yet said whether it would return Mr. Wynn’s donations. Separately, the committee paid its finance chairman’s hotels and casinos nearly $70,000 in 2017 for venue rentals, catering costs and other expenses.
Democrats pounced on harassment allegations against Wynn and began demanding their Republican opponents return donations from the casino owner.
Democratic National Committee spokeswoman Sabrina Singh in a statement Saturday criticized the RNC for its silence immediately following the Journal’s report, citing the party’s support for other candidates who have faced similar accusations of sexual misconduct.
Under Mr. Wynn’s leadership, the RNC has raised more than $121 million, according to Federal Election Commission reports covering Jan. 1 through Nov. 30, 2017. That is more than twice what the Democratic National Committee raised in the same period. Mr. Trump has frequently praised Mr. Wynn’s fundraising prowess.
—Reid Epstein and Julie Bykowicz contributed to this article.
Write to Rebecca Ballhaus at Rebecca.Ballhaus@wsj.com