While the family unit in the Gothic novel has been widely discussed, the figure of the Gothic cousin has largely been relegated to the periphery of critical scholarship. This paper contends that the cousin occupies a particularly unheimlich position in the family unit: a cousin might be of the same age, or so distant in age that they are almost a stranger; they might be entirely unfamiliar, or raised from childhood with their cousins; they might be an acceptable romantic interest or an entirely taboo one. While clearly a flexible, shifting figure within the family unit, in many Gothic novels the arrival of a cousin causes significant upheaval – either immediate or generational – that undermines, dismantles, or enacts a renegotiation of the domestic order. The intrusions of Charles in Shirley Jackson’s We Have Always Lived in the Castle and Rachel in Daphne du Maurier’s My Cousin Rachel both reflect and reinforce this trajectory. In this paper, we consider the ways in which Rachel and Charles support our interpretation of the cousin as a disruptive figure within Gothic texts.