Evidence remains limited on the effects of dietary betaine intake and dyslipidemia. We aim to investigate the association between dietary betaine intake and dyslipidemia in Chinese children and adolescents and illustrate the differences in these associations stratified by different food sources. Based on a national cross-sectional study from the China National Nutrition and Health Surveillance of Children and Lactating Mothers, 11,452 individuals aged 6-17 years were enrolled between October 2016 and December 2018. Participants were divided into quartiles according to residual energy-adjusted dietary betaine intake. The associations of dietary betaine with dyslipidemia and lipid profiles were estimated using restricted cubic spline regression and logistic regression analysis. Among the 11,452 participants, 2577 (22.5%) individuals were found to have dyslipidemia. The median (IQR) intake of dietary betaine was 56.35 (25.77, 207.66) mg/day. Negative dose-dependent associations were found between residual energy-adjusted dietary betaine intake and dyslipidemia. Compared with participants in the lowest quartile (Q1) of residual energy-adjusted betaine intake, participants in the fourth quartile (Q4) had lower odds of high total cholesterol (TC), high low-density lipoprotein cholesterol (LDL-C), high non-high-density lipoprotein cholesterol (non-HDL-C), high remnant cholesterol (RC), and dyslipidemia, with odds ratios () and 95% confidence intervals (95% CI) of 0.56 (0.45, 0.70), 0.65 (0.48, 0.87), 0.53 (0.41, 0.68), 0.42 (0.28, 0.61), and 0.79 (0.69, 0.91), respectively. Furthermore, reduced odds of high TC, high LDL-C, high non-HDL-C, high RC, and dyslipidemia were observed in dietary betaine from plant-source foods but not in animal-source foods. High intake of dietary betaine (56.35-207.66 mg/day) was associated with reduced odds of dyslipidemia, including elevated TC, LDL-C, non-HDL-C, and RC, and dietary betaine from plant-source foods revealed significant benefits for dyslipidemia in Chinese children and adolescents.