As a type of response token which involves emotional displays, interjections have received a substantial number of scholarly interests in linguistics. Yet, a paucity of research focuses on how emotion is displayed via interjections in interactions in situ. This paper focuses on how surprise and other associated emotions are accomplished via wow in Mum’s turn when interacting with the child. Using Conversation Analysis and prosody analysis, we show three major functions of wow in mothers’ turn: showing/inviting alignment and affiliation, indicating high and low engagement, and making compliments. Importantly, we argue that while affiliation-invitation/display is a generic function of wow, it could be designed as part and parcel of other actions indicating that something more is undergoing here. Data are in English.