White House Press Secretary Sarah Sanders will be leaving her post at the end of June, President Donald Trump said in a tweet on Thursday.
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.
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.
Last June, Ms Sanders dismissed rumours that she would be stepping down.