The associations between sons' challenging behaviour and mothers' anxiety and depression were investigated in four age-subgroups of boys with Autism Spectrum Disorder and their mothers (n = 49). Significant correlations were found only for the 6-yr-old boys' irritability and their mothers' anxiety (r = 0.808) and depression (r = 0.762), and for the 7-yr-old boys' stereotypy and their mothers' depression (r = 0.745). MANOVA and ANOVA found no significant differences between the irritability of the 6-yr-old boys and that of the remaining boys, nor between the 7-yr-olds' stereotypy and the remaining boys, plus no significant difference in the mothers' anxiety and depression scores across age groups. Implications are drawn for counselling and psychotherapy.