Recognizing the prominent role of parents in supporting their children with intellectual and developmental disabilities (IDD), improving quality of life for these families is an essential endeavor. While much attention has focused on the experiences of families with younger children with IDD, little is known about the family quality of life (FQOL) among families with transition-age youth and young adults. We examined the FQOL ratings of 425 parents with a child between 13–21 years of age with intellectual disability or autism to understand FQOL and the factors that may shape it. Overall satisfaction with FQOL was somewhat high for this sample, with some variability across domains. Higher FQOL ratings were predicted by lower frequency of challenging behaviors, lower support needs, and higher strength of parental religious faith. We present recommendations for research and practice focused on promoting quality of life during the transition period.