This study assessed aflatoxin B1 contamination in maize and awareness of aflatoxins in Son La province, Vietnam. Maize samples were collected from September 2016 and tested for aflatoxin B1 using ELISA kits. The prevalence of contamination above 5 μg/kg was 37.3% overall, ranging from 4% to 73.7% across districts. Contamination was higher during the rainy season. A survey of 107 people found some knowledge of mold hazards but low awareness of "aflatoxins." Ethnic minority groups had less knowledge than ethnic Vietnamese. The results can inform efforts to reduce contamination and enhance public awareness of aflatoxin risks in Son La.