Existing research has compared Family Quality of Life (FQOL) in autism spectrum disorder (ASD) populations and typically developing populations but has not yet explored differences in FQOL across ASD, attention-deficit/hyperactivity disorder (ADHD), and comorbid ASD and ADHD populations (ASD + ADHD). In the present study, 117 North American mothers of 92 sons and 25 daughters (ages 6–11) with ASD, ADHD, or ASD + ADHD completed an online survey exploring FQOL. An ANOVA failed to show group differences in overall FQOL, however, mothers of children with ASD + ADHD reported significantly lower family Emotional Well-being than mothers of children with ASD only. The results of this study provide insight into FQOL in families of children with ASD and/or ADHD. Greater research is needed in this area to understand how mothers of children with ASD, ADHD, or ASD + ADHD experience FQOL. The COVID-19 pandemic, which ran concurrent with this study, potentially influenced results.