Sibling relationships play an important role in the development of children, with the quality of these relationships being a crucial element to consider. Many factors impact sibling relationship quality, such as age or gender of the siblings, disability status, and family functioning. According to the Family Systems perspective, when one child in the family has an Intellectual Disability (ID), there are adjustments that must occur between all members of the family. This may lead to the sibling relationship looking differently compared to the relationships of typically developing (TD) siblings and may also add increased stress on the family, impacting sibling relationship quality. Previous work has investigated these topics separately, but not all together while also including multiple data sources (parent/child report and sibling interviews). The current study addressed these gaps. Fourteen families provided sibling interview data, with 13 families also completing surveys. Summaries of interviews were compiled by theme, while t-tests and correlations were used to discover that parents and TD siblings rated sibling relationships mostly equally, with siblings reporting more uninvolved relationships, while parents reported slightly more positive relationships. There also were differences in sibling relationship quality based on the communication abilities of the sibling with ID, age and gender of the TD sibling, and also levels of marital harmony and family social support. This study provides an excellent starting point for further research to examine these variables concurrently while including qualitative data from the families themselves.