Differential parenting has been considered as a nonshared objective environmental factor, referring to characteristics in the environment that differ for children in a family and may lead to different outcomes. This research proposal was built around the research question addressing differential parenting as the main focus and investigated whether children are treated differently within families relative to child specific effects, such as gender. The patterns and correlates of parents’ differential treatment of adolescent siblings in 60 two-parent families were investigated. Approximately equal number of the two sibling sex constellations (girl-boy, and boy-girl) was recruited. Overall, 30 girl-boy pairs and 30 boy-girl pairs took part. In home interviews, siblings rated 5 domains of differential treatment (e.g., privileges, chores, affection, discipline and temporal involvement) using a rating scale procedure adapted from the Sibling Inventory of Differential Experiences. Maternal differential treatment was found in case of privileges and household chores in girl-boy dyads as older daughter received fewer privileges as compared to sons. Paternal differential treatment was seen in temporal involvement as fathers spend more time with sons than daughters.