The overrepresentation of some ethnocultural minority (ECM) youth groups in the youth protection system is well documented in Quebec. Among the solutions identified to remedy this situation, the intervener-service user relationship has been identified as one of the best drivers of change. The purpose of this qualitative, phenomenological study is to 1) better understand the perceived influence of ethnocultural background on the development of the therapeutic alliance between ECM youth and their protection worker; and 2) understand, from a dyadic perspective, the similarities, differences, points of agreement, and points of disagreement in the youth-worker dyad. Fifteen ECM youth between the ages of 12 and 17 and their thirteen protection workers were interviewed in semi-structured interviews. The results make it possible to identify factors that influence the parameters of the alliance in a more specific way, including emotional bonding and agreement on goals and means. These influences, however, seem to depend on the relative importance of the cultural parameter in the relationship, highlighting the importance of prior assessment of this dimension. The implications for clinical practice, training and research are discussed.