Alexandria Mills, a soft-spoken 18-year-old from the US, 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.
In an interview after the event Alexandria Mills said: "It has changed my lifer because it's a future, it's a stepping stone for my future and I can't wait. I has not sunk in yet and to just look back and say that in the year I will have so much things happen for my life. I can change my life, I can change my situation at home, I can change my family's lifestyle, I can change my lifestyle and that's tremendously enormous."
For the final, she was wearing a shimmering ivory-coloured dress slit up the leg.
Mills takes over the title from Kaiane Aldorino of Gibraltar, who was named Miss World 2009 at a ceremony in South Africa last December.
Women from more than 100 countries participated in the contest, organisers said.
This is the 60th year of the Miss World Competition, and organisers brought back contestants from past decades to give the night a retrospective theme.
APTN