This paper examines the growing demographic phenomenon of grandparent-adult grandchild relationships from the perspectives of both generations. Drawing on qualitative life-history interviews (n = 37), this research explores the subjective meanings of the relationship, as well as the experiences of being grandparents and adult grandchildren. Despite tremendous diversity in grandparent-adult grandchild relationships, including differences among and between generations, both groups in this study view one another positively and conceptualize their ties as personally and existentially meaningful. They classify their relationships as a distinct family tie centred on unconditional love, mutual support, respect, and obligation. A number of individuals also discuss their grandparent-adult grandchild relationships as friendships, involving mutual trust, shared confidences, and personal choice. Overall, this research suggests that grandparent-grandchild relationships often grow more profound and meaningful as grandparents and grandchildren age, move through the life course, and experience life events.