This study aimed to understand farmers' knowledge, attitudes, and practices regarding agricultural pest management and synthetic pesticide use in Southeast Asia. Data were used from 900 farm households producing leaf mustard (Brassica juncea (L.) Czern. et Coss.) and yard-long bean (Vigna unguiculata subsp. sesquipedalis (L.) Verdc.) in Cambodia, Laos and Vietnam. Farmers heavily depended on synthetic pesticides as their main method of pest control. Most farmers were aware of the adverse health effects associated with pesticide use and covered body parts while spraying, but also considered pesticides to be highly effective and indispensable farm inputs. Farmers were largely unable to distinguish between common beneficial and harmful arthropods. Greater knowledge about this was associated with less pesticide use while greater awareness of pesticide health risks was associated with fewer observed poisoning symptoms. For the average farm and while controlling for other factors, farmers who sought advice from friends and neighbors used 45% less pesticide, but those who sought advice from pesticide shopkeepers used 251% more pesticide. Pesticide use was 42% less when a woman was in charge of pest management and 31% less when farmers had adopted biopesticides. These findings suggest relevant entry points for interventions aimed at reducing pesticide dependence.