Many studies have examined psychological and substance use correlates of e-cigarette use. However, several potentially important personality and substance use variables have yet to be considered. In an effort to remedy this omission, we studied the associations among e-cigarette use, personality, and substance use in a sample of 380 college students. All associations were examined for both weekday and weekend e-cigarette use. The mean age of the sample was 19.1 with a standard deviation of 1.7. Regarding current e-cigarette use, 11.8% of participants reported using e-cigarettes on weekdays and 13.9% reported weekend use. The variables most strongly associated with being an e-cigarette user versus non-user were amount of tobacco cigarette smoking, being male, taking a prescribed stimulant medication for a diagnosed medical condition, and low levels of forgiveness toward others. Two of the variables (taking a prescribed stimulant medication and low forgiveness) are novel predictors that appear to have not been previously examined. Implications of the results for understanding e-cigarette use are discussed and directions for future research are considered.