Through an online survey, this study examined the associations between horse owner attachment styles (Pet Attachment Questionnaire adjusted to horses) and personality traits (Short Five Questionnaire) with the frequency of their interactions with horses, including frequency of riding, groundwork training, and quality time with their horses, as well as headgear choices. Additionally, we investigated the associations with relationship length, number of horses owned, and whether owners are professional equestrians. We found that higher avoidant attachment was associated with less frequent interaction with horses (riding, groundwork, and quality time), while higher anxious attachment correlated with more frequent quality time. Personality traits such as conscientiousness and extraversion were positively correlated with riding frequency, while higher openness was associated with more frequent groundwork training. Owners with higher avoidant attachment were more likely to use bit-based headgear. Equestrian professionals exhibited higher avoidant attachment. Owners with one horse displayed higher anxious attachment. Longer relationships with horses were associated with lower avoidant attachment. Additionally, owners of mares exhibited higher avoidant attachment compared with those of geldings or stallions. These findings highlight the importance of understanding psychological factors in equestrian practices, offering insights into more personalized, welfare-oriented approaches to horse care and training. A better understanding of horse-owner psychology can guide the development of tailored training programs and improve human–horse interactions and relationships. Designing tools to provide equestrians with awareness of their psychological profiles could lead to better horse management and welfare.