Overweight and obesity are critical national health concerns. Recently, researchers reported that individuals who sleep less are more likely to be overweight or obese. Further research is needed to explore this relationship among specific target groups, such as undergraduates who are at great risk for both lack of sleep and overweight and obesity. This exploratory study examined the relationship among sleep, BMI, diet, and physical activity to (1) provide information on the prevalence of overweight and obesity among undergraduates; (2) provide information on whether or not undergraduates meet the basic dietary recommendations established by the 2005 Dietary Guidelines; (3) provide information on whether or not undergraduates meet the physical activity recommendations outlined by the American College of Sports Medicine; (4) provide information on whether or not undergraduates meet the National Sleep Foundations’ recommendations for sleep; (5) provide information on undergraduates’ level of sleepiness, (6) provide information on the relationship between hours of sleep per night xi and BMI among undergraduates; (7) provide information on the relationship between hours of sleep per night and dietary patterns among undergraduates; and (8) provide information on the relationship between hour of sleep per night and moderate physical activity, vigorous physical activity, strength training, and flexibility exercises among undergraduates. This study used a cross-sectional survey design, with a self-administered questionnaire to examine the relationships among diet, physical activity, sleep, and BMI among a convenience sample of 565 undergraduate college students, ages 18 – 29 years.