While research in youth mentoring is extensive in the U.S., little research has explored its effectiveness in New Zealand, despite its growth in the past 20 years. While arguments have been raised that overseas models may not fit all cultural contexts within New Zealand, there appears to be limited evidence supporting this contention. Further, little is known about associations between effectiveness and the cultural appropriateness of programs and research. This systematic review of youth mentoring programs in New Zealand is based on 26 studies that met inclusion criteria. Of those, 14 had a significant proportion (15% or more) of indigenous Māori youth and six had a significant proportion of Pasifika (Pacific Islander) youth. While almost all programs and associated research were culturally appropriate to the overall New Zealand context, they tended to be less culturally appropriate for programs working with Māori and Pasifika youth. Further, there was a negative association between cultural appropriateness and program effectiveness.