A 35-item questionnaire (DAQ: Dog Attachment Questionnaire) involving 5-point Likert responses to items designed to measure aspects of attachment to a pet/companion animal dog was constructed. The content was derived from theoretical treatments of adult human attachment, used in a broad sense as equivalent to an affectional bond. Items based on four groupings were modified for a pet dog. Two samples of dog owners (n = 112 and 306, respectively) were used to investigate the factor structure of the questionnaire, using first exploratory and then confirmatory factor analysis (CFA). The questionnaire showed high overall internal consistency, it indicated a high level of attachment to the pets, and factor analysis indicated a four-factor solution, which was replicated using CFA in Sample 2. Three of these factors produced reliable subscales, indicating (1) degree of closeness with the pet; (2) caring and protecting the pet, and companionship; (3) as a secure base and a source of emotional comfort and well-being. In sample 2, Total DAQ scores were positively related to a single-item pictorial measure of attachment to the dog, and were higher for women than men but not associated with age or duration of ownership.