Several studies have investigated the relationship between emotional attachment to pets and mental health with the majority of studies finding a negative relationship between emotional attachment to pets and mental health. Interestingly, attachment to pets differs from attachment to humans with studies showing that humans with an insecure attachment style form a particularly strong emotional attachment to their companion animals. Human attachment style is also related to mental health with secure attachment being associated with superior mental health. Building on those findings, the current study aimed at exploring the role of attachment to humans in the relationship between emotional attachment to pets and mental health. In this cross-sectional online survey (N = 610) we assessed the strength of emotional attachment to pets and attachment to humans. We further collected pet specific data as well as mental health burden in a sample of German dog owners (Mage=33.12; 92.79% women). We used a mediation model estimating the indirect link between emotional attachment to pets and mental health burden via human attachment and the direct link between emotional attachment to pets and mental health burden simultaneously. We found that attachment to humans fully mediated the positive association between emotional attachment to pets and mental health burden. A stronger emotional attachment to one's dog was associated with lower comfort with depending on or trusting in others, whereby lower comfort with depending on or trusting in others was related to higher mental health burden. Moreover, a stronger attachment to one's dog was also related to a greater fear of being rejected and unloved (Anxiety), which was, in turn, associated with a higher mental health burden. Our findings suggest that the positive link between emotional attachment to pets and mental health burden is fully accounted for by its shared variance with insecure attachment to humans in a sample mostly comprising self-identified women. Future studies need to examine whether strong emotional bonds with pets may evolve as a compensatory strategy to buffer difficult childhood bonding experiences.