Two women have become mothers. They both make art. They both grew up in a family with a sibling labelled as disabled. Ted, a visual artist, has made photographic and video work about her youngest sister. Marieke, an ethnographic filmmaker, created a short film about her eldest brother which fuelled her PhD about non-normative family lives. Intrigued by motherhood and sisterhood they start writing letters, through which they bring their memories, thoughts, artistic creations into life. This arts-based study is about entangled motherhood—i.e., the entanglement of mother-sister-daughter roles and the intergenerational entanglement of the present, past, and future—in the context of encounters with difference and care. By writing letters as a way of acting on the world and situating themselves within things, they intend to open up new forms of knowledge production, moving away from medicalized and binary ways of studying (growing up in) families with a labelled family member.