Previous research has established that short-term and persistent stress negatively impact mental health, with one proposed consequence being increased impulsivity. The present study tests the short-term and persistent associations between stress and three facets of global self-reports of impulsivity: negative urgency, lack of premeditation, and lack of perseverance, among young adults across 6 months of their first year of college. College freshmen (n = 362) completed self-report questionnaires assessing stress, negative urgency, lack of premeditation, and lack of perseverance three times over a 6-month period. Pre-registered analyses were conducted using multilevel growth curve models. Confirmatory analyses suggested that persistent stress was associated with higher levels of negative urgency and trajectories of worsening lack of perseverance over time, while short-term stress was associated with higher negative urgency. Lack of premeditation was not robustly associated with stress. While both persistent and short-term exposure to stress may be associated with some facets of global self-reports of impulsivity, the relations vary across facets of impulsivity. Overall, negative urgency was the most robustly associated with stress on both time scales, which suggests that this facet of impulsivity may be the most impacted in the context of stress in the first year of college. © 2022 Wiley Periodicals LLC.