Siblings are often the main social partners in people’s lives and thus play important roles. In comparison with other family members, siblings are likely to remain in our lives for longer and play more roles. Previous studies suggest that gender can influence these roles. We conducted a qualitative study using semistructured interviews to examine individuals’ perceptions of gender-based sibling roles, with a maximum variation sample of 21 Iranian adults. Interview transcriptions were analyzed by dividing them into two content areas: sisters’ roles and brothers’ roles. Six main role categories emerged for sisters’ roles, whereas four emerged for brothers. "Support," "Service," and "Dominance" were three common categories between genders. "Consideration," "Mediation," and "Counseling and Guidance" categories emerged for sisters, and "Control" emerged for brothers. These findings suggest that Iranian society presents some unique domains of gender-based sibling roles. We discussed implications for research and practice and the limitations of our study.