Objective: To identify factors associated with owners not walking with their dog. Method:Dog owners (n = 629) taking part in the RESIDE study, Perth, Western Australia completed a self-administered questionnaire in 2005–06 that included items about the dog, dog–owner relationship, dog walking and intrapersonal and environmental factors associated with dog walking. Physical activity data were also collected using NPAQ. Results:Overall, 23% of dog owners did not walk with their dog. More dog walkers achieved 150 min of physical activity/week than owners who did not walk with their dog (72% vs. 44%, p <0.001). Not walking with a dog was significantly more likely in owners who did not perceive that their dog provided motivation (OR 9.60, 95% CI: 4.37, 21.08) or social support (OR 10.84, 95% CI: 5.15, 22.80) to walk, independent of other well-known correlates of physical activity. Conclusion: There would be a significant impact on community physical activity levels if owners who do not walk with their dog could be persuaded to begin dog walking. Understanding the factors that discourage or facilitate owners to walk with their dog will assist in tailoring interventions designed to encourage both the uptake and maintenance of regular dog walking.