Objective: This study examined the impact of family size and type on maternal rejection and its relationship with emotional-behavioral difficulties in children with ADHD compared to those typically developing. Method: The participants were mothers of 7- to 12-year-old children with ADHD (n = 102) and mothers of typically developing children (n = 102) in Kazakhstan. In this cross-sectional study, multiple linear regression analysis was performed to explore the relationship between variables. Results: Family size affected maternal rejection after accounting for children's emotional-behavioral difficulties only in mothers of children with ADHD. The effect of family type on maternal rejection was statistically significant in both groups. Family size exacerbated the relationship between children's emotional-behavioral difficulties and maternal rejection only in children with ADHD. The moderating effect of family type was not found in either group. Conclusion: Our findings suggest that family size and type contribute to maternal rejection of children with ADHD.