Homelessness is a pervasive social issue worldwide. In the UK, it is currently estimated that one in two hundred people are homeless, approximating 0.5% of the population. Pet ownership among this group is thought to be commonplace and has been linked with a range of human health and social benefits. These include amelioration of loneliness, isolation and depression and reduction in suicidal thoughts, substance misuse and criminal activity. However, pet ownership has also been suggested to perpetuate homelessness by restricting access to support services, especially housing. This study aimed to explore the nature of the Human-Companion Animal Bond (H-CAB) between UK homeless owners and their dogs, and to document the implications of this bond for the health and welfare of both parties. Twenty homeless or vulnerably housed dog owners were recruited to participate in semi-structured interviews consisting of open and closed questions. These were recorded, transcribed and subjected to thematic analysis. Major emergent themes included participants' descriptions of their pets as kin; the responsibility they felt towards their pet; and anticipatory grief when contemplating a future without their companion animal. Importantly, the analysis also suggests the importance of a mutual rescue narrative, whereby pet owners felt that they had rescued their dogs from a negative situation, and vice-versa. However, participants also described being refused access to services, frequently on account of their desire not to relinquish their pet. Indeed, given their description of their pets as family members, participants expressed frustration that this relationship was not considered as being of worthy of preservation by homelessness services. This study has highlighted some important features of the H-CAB between homeless owners and their dogs, not previously characterized in the UK. It also highlights the importance of empowering support services to accept pets where feasible, and thus preserve and enhance the benefits of pet ownership in this vulnerable population.