College can be a time of immense stress. Mindfulness meditation has been shown to be an effective stress management technique. A significant limitation of the mindfulness literature, however, is a reliance on inactive control groups. We compared a mindfulness intervention with both an ecologically valid, active control (interacting with a dog during a group study break) and a no-treatment control. Participants (n = 74) were randomly assigned to groups, with the treatment groups completing 4 weekly sessions (duration: 1 hr). By the end of the 4th session, those in the mindfulness group exhibited significantly lower state anxiety compared with those in the other groups, while the dog group was also significantly less anxious than the control group. In addition, both the dog and the mindfulness groups exhibited significantly less dysphoric affect than the control group. All of the participants came in for a posttreatment assessment during which they were given a cognitive stressor challenge. Electrocardiogram data were collected during the cognitive challenge allowing us to assess heart rate variability (HRV)—a measure of the body’s ability to modulate the physiological stress response. Participants in the mindfulness group exhibited significantly higher HRV during the cognitive challenge than those in the other 2 groups, signifying a more-adaptive response to stress (p < .05). Individuals in the dog group, meanwhile, were no different from control participants. These preliminary findings suggest that brief mindfulness training can help college students manage their stress in response to the ubiquitous academic and cognitive challenges of college life.