There are specific guidelines for forensic interviews with children [for example, Crown Prosecution Service. (2011). Achieving best evidence in criminal proceedings: Guidance on interviewing victims and witnesses, and guidance on using special measures. London: Crown Prosecution Service]. Such guidelines include a set of “ground rules” – these are procedures that should be followed at the start of an interview to explain the nature of the interview to a child and to ensure that evidence is obtained in a legally appropriate way. The procedures are also used as a way to demonstrate how well a child understands aspects of the interview. This study investigated how ground rules were implemented in 51 investigative interviews with child witnesses and victims alleging criminal activities. The results showed that there was a lack of consistency in ground rule implementation, and that even when ground rules were implemented, their relevance to the remainder of the interview was not made clear. These findings highlight concerns as to the efficacy of ground rule implementation practices.