Objective: Examine how changes in sleep duration, objectively measured by activity trackers, impact weight gain in incoming college freshman. Participants: Incoming college freshmen, age [greater than equal to] 18. Methods: We measured weight and daily sleep duration before college entry and through the 1st college quarter. Additionally, we examined changes in sleep variability, activity levels and smartphone screen time use as possible predictors of weight gain. Results: 75 participants completed the study. Total sleep duration decreased from 437.9 ± SD 57.3 minutes at baseline to 416.5 ± SD 68.6 minutes by the end of the first quarter (p = 6.6 × 10[superscript -3]). (BMI) did not change significantly in this cohort. Higher sleep variability at baseline and an increase in sleep variability were associated with increases in BMI. Smartphone screen use was note to be high (235.2 ± SD 110.3 minutes/day) at the end of the first quarter. Conclusions: College weight gain may be affected by factors other than sleep duration, including sleep variability.