Scant research exists regarding how family cohesion is related to relationships among siblings with and without disabilities. The purpose of this study, based upon the Double ABCX Model of Adaptation, was to investigate cohesion and sibling relationships in families raising typically developing siblings (TDC) and families raising children with some type of disability. Mothers and fathers of 221 sibling pairs completed demographic, family cohesion, and sibling relationships questionnaires. Paired t-tests, correlations, and structural equation modeling were used to analyze the data. Mothers reported higher levels of family cohesion than fathers. Comparing families raising TDC with families raising a child with some type of disability, parents of TDC reported higher cohesion than parents of children with autism spectrum disorder (ASD); fathers of TDC reported higher cohesion than fathers of children with Down syndrome (DS). However, parents of TDC reported less positive sibling relationships than parents of DS. Higher levels of cohesion correlated with more positive sibling relationships. It was concluded that relationships exist between family cohesion and sibling relationships, and these perceptions differ between families raising children with or without disabilities. Implications for research and practice are discussed.