Decades of research highlight that differential treatment can have negative developmental consequences, particularly for less favored siblings. Despite this robust body of research, less is known about which children in the family tend to be favored or less favored by parents. The present study examined favored treatment as predicted by birth order, gender, temperament, and personality. We also examined whether links were moderated by multiple factors (i.e., parent gender, age, reporter, domain of parenting/favoritism). Multilevel meta-analysis data were collected from 30 peer-reviewed journal articles and dissertations/theses and 14 other databases. In all, the data reflected 19,469 unique participants (Mage = 19.57, SD = 13.92). Results showed that when favoritism was based on autonomy and control, parents tended to favor older siblings. Further, parents reported favoring daughters. Conscientious and agreeable children also received more favored treatment. For conscientious children, favoritism was strongest when based on differences in conflict (i.e., more conscientious children had relatively less conflict with their parents). Parents and clinicians should be aware of which children in a family tend to be favored as a way of recognizing potentially damaging family patterns. (PsycInfo Database Record (c) 2025 APA, all rights reserved).