Objective: To investigate the correlation between social jetlag and psychological behavior in upper primary school students,so as to provide reference for sleep health promotion in primary school students. Methods: From April to June 2024, a survey was conducted among 4 341 fourth and fifth grade students from 9 public primary schools in a district in Beijing. Sleep patterns were assessed using a self designed questionnaire, while psychological behavior was evaluated using the Strengths and Difficulties Questionnaire (SDQ)(parent version). A generalized estimating equation (GEE) model was used to examine the association between different levels of social jetlag and psychological behavior problem scores in primary school students. Results: The proportions of students with social jetlag of <1.0, 1.0-<2.0, and ≥2.0 h were 57.6%, 30.6%, and 11.8%, respectively. The GEE model analysis found that after adjusting for covariates, compared with primary school students with social jetlag of <1.0 h, those with 1.0 -<2.0 and ≥2.0 h had higher scores for internalizing behavior problems [ β (95% CI ) =0.23(0.05-0.41)，0.28(0.02-0.54), P < 0.01]. Primary school students with ≥2.0 h of social jetlag had higher scores for externalizing behavior problems [ β (95% CI )=0.42 (0.13-0.71)， P <0.01]. Among boys and primary school students with an average nighttime sleep duration of ≥9 h, comparied with social jetlag of <1.0 h,those with sucial jetlag 1.0-<2.0 h had higher scores on internalizing and externalizing behavior problems[ β (95% CI )=0.32(0.07-0.56),0.51 (0.11-0.90), 0.26 (0.06-0.46)，0.58 (0.25-0.91), P <0.05]. Conclusions Greater social jetlag may be a risk factor for internalizing and externalizing behavior problems in upper primary school students. Reducing social jetlag may help decrease the occurrence of psychological behavior problems in primary school students.