18-year-old, was named the winner in Saturday night's contest in southern China. The tall blonde was a relative surprise winner after speculation focused on other contestants.
Second place went to Emma Wareus of Botswana, and Adriana Vasini of Venezuela came third.
The host country's own contestant, Tang Xiao, also was among the final five.
According to a brief biography on the Miss World website, Mills calls Louisville, Kentucky, her hometown, and she recently graduated from high school. She would like to become a teacher.
"I've never met a stranger and enjoy meeting new people," she says in the bio.
For the final, she was wearing a shimmering ivory-colored dress slit up the leg.
