At a White House panel discussion on women empowerment, Trump said US ambassador to the United Nations Haley, 45, is a tough competitor and is doing her job "fantastically well".
The discussion was joined by Indian-American Seema Verma, who holds a key healthcare position in the administration, and First Lady Melania Trump made a rare appearance at the event.
"My Cabinet is full of really incredible women leaders. Administrator Linda McMahon, who has been a friend of mine for a long time. She's done an incredible job in business. Administrator Seema Verma, Secretary Betsy DeVos, and, of course, my good friend from South Carolina who is a very tough competitor - Nikki Haley," Trump said.
US Vice President Mike Pence described Haley as "cool" and said she is a favourite of one of his two daughters.
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"We are so honoured to have you in this administration," Pence said.
White House Press Secretary Sean Spicer told reporters that the Trump administration is "committed to empowering women in the workplace."
Trump had made women empowerment a priority throughout his presidential campaign, when he spoke on affordable childcare and paid family leave, investing in women's health, and the barriers faced by female entrepreneurs and business owners, Spicer claimed.