Background: Several studies have reported positive associations between pet ownership and a variety of health outcomes. In this study, we explored associations between pet ownership and physical activity in a large, ethnically diverse population-based sample in California. Method: Data from the California Health Interview Survey (CHIS) were used to assess the associations between pet ownership (ie, dog, dog and cat, cat, and non–pet owners) and transportation and leisure walking in a sample of 41,514 adults. Logistic regression was used to assess associations between pet ownership and type of walking, and linear regression was used to assess associations between pet ownership and total minutes walking per week. Results: Dog owners were slightly less likely to walk for transportation than were non–pet owners (OR = 0.91; 95% CI: 0.85 to 0.99) but more likely to walk for leisure than non–pet owners (OR = 1.6; 95% CI: 1.5 to 1.8) in multivariate analyses. Overall, dog owners walked 18.9 (95% CI: 11.4 to 26.4) minutes more per week than non–pet owners. Walking behaviors of cat owners were similar to non–pet owners. Conclusion: Our findings support the moderate association between dog ownership and higher levels of physical activity.