This entry describes the principles of third-party policing (TPP) on the example of the Family Engagement Strategy (FES). The FES is a police-led partnership approach, tailored to reduce the need for police interventions among high-risk families and juveniles. Key principles of TPP are described. Their application is illustrated on the example of the FES, to highlight some of the key benefits and challenges inherent to TPP. This entry highlights the usefulness of TPP principles to both high-risk target populations and agencies involved in TPP models.