<p>The human animal bond is frequently linked to improved well-being, yet this benefit may be undermined by socioeconomic, health and environmental challenges that may jeopardise guardians’ ability to maintain their relationship with their pets. This study examines how social determinants of health (SDH) impact pet retention and relinquishment in Australia. A mixed-methods approach was used, integrating quantitative and qualitative data from 400 Australian pet guardians via an online survey. Participants were recruited through Prolific and completed a QuestionPro survey assessing demographics, housing stability, financial constraints, health, social support, and if they had relinquished or considered relinquishing a pet. Quantitative analysis (IBM SPSS Statistics) explored associations between SDH factors and pet relinquishment, while qualitative thematic analysis identified key challenges. Housing instability, particularly among renters, was significantly associated with considering relinquishment (<i>p</i> = 0.001). Lower education levels were associated with higher relinquishment rates (<i>p</i> = 0.004). Qualitative findings revealed that challenges were rarely experienced in isolation. Instead, participants often faced multiple, intersecting challenges, such as rental restrictions, financial strain, and health issues as major barriers to pet guardianship, which collectively intensified the risk of relinquishment. Securing pet-friendly rentals emerged as the most prominent concern influencing guardianship decisions. Social support networks played a protective role, aiding guardians in retaining their pets during difficult times. Findings highlight the need for pet-friendly housing, financial support including for veterinary care, and integrated human-animal welfare programs to reduce relinquishment risks. Targeted interventions are crucial to protecting the human-animal bond and improving welfare outcomes for both guardians and pets.</p>