Literature on the delivery and impact of foster parent training, such as the Nurturing Parenting Program (NPP), is sparse, particularly for relative foster parents. This study investigates (a) how NPP referral, initiation, and completion rates vary between relative and non-relative foster parents, (b) reasons for not initiating NPP, and (c) changes in parenting attitudes and behaviors for relative and non-relative foster parents after participating in NPP. The study analyzed data from the Illinois Birth to Three (IB3) study for 722 relative and 397 non-relative foster parents of children ages three and younger. Relative and non-relative foster parents had similar NPP referral and initiation rates, but relatives had significantly lower completion rates. Content analysis of case notes for 498 cases showed that relative foster parents more frequently noted barriers (e.g., childcare, transportation) to NPP initiation. Among NPP completers, both groups reported similar levels of improvements in parenting attitudes and behaviors at the end of NPP, but a pattern of lower scores was observed for relative foster parents. The findings suggest a need for more support for foster parents, particularly relative foster parents.