This study distinguishes between direct and indirect ratings of parental differential treatment (PDT) and targets their unique contributions in predicting siblings’ socio-emotional adaptation. Questionnaire data were gathered in 435 families with (minimum) two non-twin siblings in middle childhood. Two siblings reported about PDT, parents reported about conduct problems and emotional symptoms in siblings. Because aspects of PDT tend to be intertwined in research, we delineated ‘parenting differences’ following siblings’ differing developmental needs from ‘favoritism’ or perceived parental partiality. We separately measured (a) parenting differences and (b) favoritism, both with (c) indirect and (d) direct measures. Indirect parenting differences were calculated by subtracting parenting scores towards each sibling and included positive parenting, negative behavioral control and psychological control. Direct parenting differences were gathered by asking the children to compare parental treatment and included support, strictness and responsibility/autonomy demands. Measures of favoritism explored if one of the siblings received ‘better treatment’ than the other. Multilevel analyses with child perceptions of PDT and child emotional and conduct problems were conducted (parenting differences and favoritism) in a multi-informant design. Reports of favoritism were less frequent than reports of parenting differences and direct scores yielded lower estimates of differentiation than indirect scores. Differences in responsibility/autonomy demands were quite unrelated to perceptions of favoritism. Especially paternal PDT was related to child problem behavior. Siblings who received more negative behavioral control and perceived more strictness displayed more conduct problems. Favoritism was related to higher levels of problem behavior, regardless of which sibling received favored treatment.