The 20-year-old beamed as she posed for pictures in a £5,300 Dior outfit after accepting the honour, awarded for services to tennis, at an investiture ceremony at Windsor Castle on Tuesday.
She was accompanied by her father Ian, who has been a guiding influence during her rise to tennis stardom.
She was made a Member of the Order of the British Empire after her US Open victory in 2021 made her the first British woman to win a grand slam since Virginia Wade in 1977 – and the first qualifier of any nationality to do so.
The victory over Canadian – and fellow teenager – Leylah Fernandez 6-4 6-3 at Flushing Meadows came when she was 18.
In a statement issued by her agent after the ceremony, she said: “It’s been great to receive my honour today from his Majesty the King – I feel extremely grateful.”
Labour MP Dame Nia Griffith, who collected her honour at the same ceremony, said of Ms Raducanu: “I think it is fantastic seeing a young person (achieve) the success that she had and I think obviously now she faces that incredibly challenging situation of coping with that success and coping also with disappointment.
“And I certainly think it is wonderful to see young people being praised and being rewarded and let’s make sure we give every young person the opportunities so that they can develop their talents to the full.”
Also on Tuesday, Sir Isaac Julien, the Turner prize-nominated artist and filmmaker, was set to collect a knighthood for services to diversity and inclusion in art.
Former footballer Gary Bennett, patron of the Show Racism The Red Card group, is among the other MBE recipients, as is former Test cricketer Hugh Morris.
The batsman has been awarded an MBE for services to cricket and charity.