Governor Haley will suspend her presidential campaign Wednesday after being soundly defeated across the country on Super Tuesday, according to people familiar with her decision, leaving President Trump as the last remaining major candidate for the 2024 Republican nomination.

Three people with direct knowledge who spoke on the condition of anonymity because they weren’t authorized to speak publicly confirmed Haley’s decision ahead of an announcement by her scheduled for Wednesday morning.

Mrs. Haley is not planning to endorse Mr. Trump in her announcement, according to the people with knowledge of her plans. Instead, she is expected to encourage him to earn the support of the coalition of moderate Republicans and independent voters who supported her.

Mrs. Haley, a former South Carolina governor and U.N. ambassador, was Mr. Trump’s first significant rival when she jumped into the race in February 2023. She spent the final phase of her campaign aggressively warning the GOP against embracing Mr. Trump, whom she argued was too consumed by chaos and personal grievance to defeat President Biden in the general election.

Her departure clears Mr. Trump to focus solely on his likely rematch in November with Mr. Biden. The former president is on track to reach the necessary 1,215 delegates to clinch the Republican nomination later this month.

Mrs. Haley’s defeat marks a painful, if predictable, blow to those voters, donors and Republican Party officials who opposed Mr. Trump and his fiery brand of “Make America Great Again” politics.

She was especially popular among moderates and college-educated voters, constituencies that will likely play a pivotal role in the general election. It’s unclear whether Mr. Trump, who recently declared that Mrs. Haley donors would be permanently banned from his movement, can ultimately unify a deeply divided party.

Mr. Trump on Tuesday night declared that the GOP was united behind him, but in a statement shortly afterward, a Haley spokeswoman, Olivia Perez-Cubas, said, “Unity is not achieved by simply claiming, ‘We’re united.’”

“Today, in state after state, there remains a large block of Republican primary voters who are expressing deep concerns about Donald Trump,” Ms. Perez-Cubas said. “That is not the unity our party needs for success. Addressing those voters’ concerns will make the Republican Party and America better.”

Mrs. Haley leaves the 2024 presidential contest having made history as the first woman to win a Republican primary. She beat Mr. Trump at the District of Columbia on Sunday and in Vermont on Tuesday.

She had insisted she would stay in the race through Super Tuesday and crossed the country campaigning in states holding Republican contests. Ultimately, she was unable to knock Mr. Trump off his glide path to a third straight nomination.