Many people, including nearly half of American households, own a pet dog. Previous work has found that therapy dog interactions reduce distress, but little work to date has empirically established the mood-enhancing effects of interaction with one's own pet dog. In this study, dog owners (N = 73; 86.3% female, 13.7% male; age 25-77 years) underwent a stress-inducing task followed by random assignment to either (a) interacting with their dog (n = 24), (b) an expectancy control (n = 25; "stress-reducing" coloring books), or (c) a waiting control (n = 24). We compared the effects of each condition on affect and state anxiety. Participants assigned to the dog interaction showed greater increases in positive affect, as well as greater reductions in anxiety compared to both expectancy and waiting controls (ds > 0.72, ps < .018). No significant reductions in negative affect were detected. Second, we found that self-reported experiences with animals, attitudes toward animals, or bondedness with their dog did not differentially predict the condition's impact on the owner's mood. Finally, we coded participants' degree of engagement (e.g., time spent playing) with the dog and found that higher engagement predicted reduced negative affect. Overall, interacting with one's own pet dog reduced owners' distress. Such interactions, which occur commonly in daily life, may have the potential to alleviate distress at a large scale. Precisely how this works and for whom it is especially well suited remain intriguing open questions. (PsycInfo Database Record (c) 2024 APA, all rights reserved).