Background: Despite accumulating evidence showing that sleep duration and cardiometabolic health are correlated, the association of sleep regularity and quality with cardiovascular risk factors in children and adolescents remains inconclusive. Therefore, we examined the relationship between sleep regularity/quality and cardiovascular risk factors in children and adolescents in Macao, China. Methods: We conducted a cross-sectional study among primary and secondary school students (age range: 9–18 years) in Macao, China. Body weight, height, waist circumference (WC), and serum lipid levels were measured. Sleep regularity and sleep quality were assessed by using the Pittsburgh Sleep Quality Index. Multivariable logistic regression was conducted to examine the relationship of sleep variables with the increased likelihood of body mass index (BMI)-classified overweight/obesity, WC-classified obesity, and dyslipidemia. Results: A total of 1078 school students were included in the analysis. Differences of >2 hours between weekday and weekend bedtimes were associated with the increased risk of BMI-classified overweight/obesity (odds ratio = 2.58, 95% confidence interval = 1.55–4.31, p < 0.01) after being adjusted for sleep variables and lifestyle factors. No statistically significant association was found between poor sleep quality and any other outcome. Conclusions: Irregular bedtime was associated with elevated body weight regardless of sleep amount and quality. Thus, regular bedtimes are recommended as a simple but practical strategy for preventing obesity.