White House spokeswoman Sarah Sanders will leave her job at the end of the month, says President Donald Trump.
Mr Trump said Ms Sanders would be returning to her home of Arkansas after more than three years on the job.
"She is a very special person with extraordinary talents, who has done an incredible job," Mr Trump wrote.
She started out as deputy press secretary before replacing Sean Spicer in the top post in July 2017.
Mrs Sanders has been a fierce defender of the president, famously saying that God "wanted Donald Trump to become president".
She had a combative relationship with the media, often repeating her boss' allegation of fake news.
But White House press conferences have become increasingly rare during her tenure.
Her last media briefing was held on 11 March - 94 days ago.
Mrs Sanders held fewer briefings than any of the preceding 13 press secretaries, according to the American Presidency Project.
Mr Trump has opted to take charge of his own media relations by making impromptu remarks to journalists on the South Lawn of the White House when he departs on the presidential helicopter Marine One for various engagements.
Mrs Sanders' time in the post was not without controversy, and she was accused of making false claims to journalists.
After Mr Trump fired FBI Director James Comey in May 2017, she told reporters she had "heard from countless members of the FBI that are grateful and thankful for the President's decision".
But she told special counsel Robert Mueller, during his investigation into whether the Trump election campaign had colluded with Russia, that this claim was "a slip of the tongue" that was "not founded on anything".
Last June, Mrs Sanders dismissed rumours that she would be stepping down.
Mrs Sanders is the daughter of Mike Huckabee, who served as the governor of Arkansas from 1996 to 2007.
In his tweet announcing Mrs Sander's pending resignation, Mr Trump wrote that he hoped she would run for the same position.
"She would be fantastic," he said.
- BBC / Reuters