She becomes the first-ever Vietnamese winner of the competition, which is themed around promoting environmental awareness.
Alongside Miss World, Miss Universe, and Miss International, Miss Earth is one of the Big Four most coveted pageants.
Brunette stunner Khanh is a marketing student who is fluent in both Vietnamese and English.
Born and raised in the coastal Vietnamese province of Bến Tre, she was crowned at a ceremony in Manila, the Philippines on Saturday.
Khanh claims to be a vocal defender of the environment and highlighted a project to protect wildlife in the Mekong Delta close to her home in her 2018 pageant video.