ObjectiveThis study applied the Family Systems Illness Model to examine how child disorder severity influences mental health in mothers and fathers of children with chronic (mainly developmental) disorders (CD). MethodsWe measured parental mental health and perceived child disorder severity among 204 mothers and 125 fathers of 220 children with CD and compared the mental health scores with norms. We analyzed how much of the variance in parental mental health was explained by child disorder severity, including discrepancy between maternally and paternally perceived severity. ResultsCompared to norms, we found elevated mental health problems in both mothers (d = 0.45) and fathers (d = 0.20) of children with CD. Mothers had higher scores than fathers on both mental health problems (d = 0.63) and severity (d = 0.43). Perceived disorder severity was similarly associated with mental health problems for mothers (β = 0.23) and fathers (β = 0.34). Discrepancy between maternal and paternal perceived disorder severity did not influence parental mental health. ConclusionFindings suggest gender-specific challenges in parenting children with CD. Subjective perception of disorder severity plays a substantial role for parental mental health. InnovationThis comparative study of mothers and fathers contributes to a predominantly mother-focused field.