The 24-year-old Filipino-Australian was in shock as Miss Universe 2017, Demi-Leigh Nel-Peters of South Africa, handed her the crown.
Born in Cairns, Queensland, Gray is the daughter of an Australian father and Filipina mother.
She studied at the Berklee College of Music in Boston in America.
Gray explained that she wore a sparkling red dress inspired by Mayon Volcano in the Philippines because “when I was 13 my mum said she had a dream that I would win Miss Universe in a red dress“.
Miss South Africa, Tamaryn Green came second, while Miss Venezuela, Sthefany Gutierrez placed third.
Miss Australia, Francesca Hung, made the top 20 but missed out on the top 10.