Objective: To analyze the association between poor sleep characteristics and the coexistence of negative emotions and overweight/obesity among college students, so as to provide a scientific basis for improving their physical and mental health. Methods: From November to December 2023, a convenience sampling method was used to survey 6 600 college students from nine universities in Jiangxi, Hunan, and Hubei provinces. The Depression Anxiety and Stress Scale-21 (DASS-21), Insomnia Severity Index (ISI), Pittsburgh Sleep Quality Index (PSQI), and physical examinations were employed to assess negative emotions, poor sleep characteristics, and overweight/obesity. Chi square test and Logistic regression were used to analyze the impact of poor sleep characteristics on the coexistence of negative emotions and overweight/obesity. Results: The coexistence rates of different categories of negative emotions (depression, anxiety, stress) and overweight/obesity were 6.1% ( n= 405), 8.0% ( n =529), and 3.3% ( n =217), respectively. Gender, grade level, major, maternal education level, annual family income, physical activity level, only child status, and carbonated beverage consumption were statistically associated with the coexistence rates of different categories of negative emotions and overweight/obesity ( χ 2=4.01-35.18, all P <0.05). Logistic regression analysis showed that after adjusting for gender, grade level, major, only child status, maternal education level, annual family income, physical activity level, and carbonated beverage consumption, poor sleep characteristics were significantly associated with an increased risk of the coexistence of negative emotions and overweight/obesity ( OR =1.41-6.65); moderate and poor sleep quality levels were significantly associated with an increased risk of the coexistence of different categories of negative emotions and overweight/obesity among female students ( OR =1.99-4.71) (all P <0.05). Conclusions Poor sleep characteristics are associated with the coexistence of negative emotions and overweight/obesity among college students. Greater attention should be paid to sleep issues in this population, and sleep education should be actively promoted to reduce the risk of comorbid negative emotions and overweight/obesity.