Background As individuals with intellectual and developmental disabilities (IDD) grow older, siblings are likely to become caregivers for their brothers and sisters with IDD. Thus, it is important to identify the correlates of sibling caregiving to facilitate transitions to caregiving roles. Method This study involved the secondary analysis of a national data set of 429 adult siblings of individuals with IDD. Results Current sibling caregiving was positively correlated with sibling relationship quality, sibling advocacy and future planning, maladaptive behaviours of individuals with IDD, and family size. Current sibling caregiving was negatively correlated with parent caregiving abilities and functional abilities of individuals with IDD. Further, among siblings who provided care, the level and nature of sibling caregiving were negatively correlated with parent caregiving abilities. Conclusions The results identify the correlates of current caregiving among siblings of individuals with IDD. More research is needed to understand current sibling caregiving.