BACKGROUND: The "caregiver burden" experienced by pet owners arises from the challenges and strains of caregiving, reflecting the complex relationship between humans and their pet animals and significantly impacting the quality of life of both humans and pets. This study aimed to quantitatively analyze the caregiver burden among South Korean pet owners and examine the various factors contributing to its formation. METHODS AND MATERIALS: A total of 766 dog and/or cat owners who identified themselves as primary caregivers were recruited through an online research panel. Participants completed questionnaires assessing pet and owner characteristics, including pet health status, attachment to the pet, caregiving support from family or others, and veterinary services. Statistical analyses, including regression analysis, were conducted using SPSS version 26. RESULTS: The final regression model identified several factors associated with higher caregiver burden, including younger age (of both the pet and caregiver), caregiver gender (male), pet health status (acute or curable condition), level of support from others (lower emotional but higher financial and practical support), and higher frequency of veterinary communication for pet care. While strong attachment to pets may help alleviate caregiver burden, its effects are complicated and require careful consideration. CONCLUSIONS: Pet caregiver burden is shaped by a combination of pet-related, individual, and contextual factors. This study highlights the need for a relationship-centered approach to veterinary care that addresses the unique challenges faced by caregivers to enhance caregiver well-being and optimize pet welfare.