Kreuk was born in Vancouver. Her father, Peter Kreuk, is of Dutch descent; her mother, Deanna Che, is of Chinese descent, but was born in Indonesia; her maternal grandmother was born in Jamaica of Chinese descent. Both parents are landscape architects. She has a sister named Justine, who is about five years younger. Kreuk trained in gymnastics at the national level until high school but quit in 11th grade due to scoliosis. She attended Edith Cavell Elementary School and Eric Hamber Secondary School in Vancouver.

She had plans to study psychology, environmental science, or forensic science at Simon Fraser University when a casting director for the CBC TV series Edgemont contacted her secondary school, looking for an exotic-looking girl to play the part of a Chinese Canadian, Laurel Yeung on the Vancouver-shot show. Kreuk's drama teacher convinced Kreuk, who had no previous acting experience other than in musicals at her high school, to audition for the role. To her surprise, she won the part.