The role of the dog has changed significantly throughout the history of Western society, from a predominantly working role to the role of a pet in an increasing number of households. Therefore, more and more attention is being given to research on the relationship between humans and dogs. There are many factors that affect the quality of the relationship between owners and their dogs, and personality traits are among them. The aim of this study was to examine the relationship between owners' and dogs' personality traits and the quality of their relationship. Statistical analysis was conducted on a sample of 455 female participants, aged between 18 to 74 years (M=37.07, SD=11.49). Data were collected online and the instruments used were the HEXACO-60 personality inventory for measuring the owner's personality traits, the Dog Personality Questionnaire (DPQ) for measuring dog's personality traits and the Monash Dog Owner Relationship Scale (MDORS) for measuring the quality of owner-dog relationship. The study found significant associations between owner personality traits honesty-humility and dog personality traits fearfulness and aggression towards animals, owner personality trait emotionality and dog personality traits fearfulness and responsiveness to training, owner's extraversion and fearfulness, aggression towards animals and responsiveness to training in dogs, and conscientiousness in owners and fearfulness and activity/excitability in dogs. The results also show that significant predictors of owner-dog interaction are owner personality trait extraversion and dog personality traits responsiveness to training and aggression towards animals. Significant predictors of perceived emotional closeness were owner personality trait emotionality and dog personality trait responsiveness to training, while for subscale perceived costs, significant predictors were owner's honesty-humility and extraversion and dog personality trait responsiveness to training.