Although recent emotion regulation research has identified effective regulatory strategies that participants can employ during single experimental sessions, a critical but unresolved question is whether one can increase the efficacy with which one can deploy these strategies through repeated practice. To address this issue, we focused on one strategy, reappraisal, which involves cognitively reframing affective events in ways that modulate one's emotional response to them. With a commonly used reappraisal task, we assessed the behavioral correlates of four laboratory sessions of guided practice in down-regulating responses to aversive photos. Two groups received practice in one of two types of reappraisal tactics: psychological distancing and reinterpretation. A third no-regulation control group viewed images in each session without instructions to regulate. Three key findings were observed. First, both distancing and reinterpretation training resulted in reductions over time in self-reported negative affect. Second, distancing participants also showed a reduction over time in negative affect on baseline trials in which they responded naturally. Only distancing group participants showed such a reduction over and above the reduction observed in the no-regulation control group, indicating that it was not attributable to habituation. Third, only participants who distanced reported less perceived stress in their daily lives. The present results provide the first evidence for the longitudinal trainability of reappraisal in healthy adults using short courses of reappraisal practice, particularly using psychological distancing.