Objective: To explore prevalence and associated factors of neglect among left-behind middle school students in undeveloped area of Guangdong, and to provide scientific basis for effective intervention measures. Methods: A total of 1 105 middle school students were selected from Yangjiang and Qingyuan by random cluster sampling, neglect and left-behind was assessed by a self-reported questionnaire. Results: The prevalence of neglect was 70.9% among left-behind middle school students aged 11-17 years in Yangjiang and Qingyuan areas. Univariate analysis suggested that high parental education, democratic and strict parenting, and frequent contacts with parents associated with low rate of neglect (P<0.05). After adjusted for gender, parental education, parenting style, contact frequency, Logistic regression analysis revealed that parenting discipline(rough, cold, capricious)(OR=2.01, 95%CI=1.23-3.26), contact with parents more than once every two weeks (OR=1.75, 95%CI=1.12-2.72) , peer or self-care (OR=1.85, 95%CI=1.04-3.30) were positively associated with neglect, while higher mother education was negatively associated with neglect. Conclusion The prevalence of neglect is high among left-behind students in Yangjiang and Qingyuan, which deserves further attention from family, community, school and government to promote healthy development.