Since December 2000, the Family Law Act 1975 (Cth) has allowed Australian married couples to enter into a legally binding financial agreement before or during marriage covering how their property and financial resources will be divided if their marriage ends. The legislation was extended to de facto couples in 2009. Concern has mainly surrounded agreements entered before or early on in relationships ('prenups'), yet there is very little research on how these are being utilised by lawyers and their clients. Our research, involving interviews with 40 family lawyers in 2020-2021, aimed to address this gap. One of the clearest themes that emerged in interviews was the role of the families of the couple as the driving force behind entry into prenups. This paper explores how lawyers described the involvement of family members, and couples' and lawyers' responses to that involvement. Our findings demonstrate that to understand the dynamics of a prenup, we often must also consider the broader family relational context in which it emerges. This places in question the notion that the prenup is simply a contractual arrangement between two people (the couple); rather, it may be a product of 'extended' family influence