The study evaluated the impact of solution-focused brief therapy (SFBT) group-work on the post-traumatic growth (PTG) of mothers who have a child with ASD. A quasi-experimental design was used in which 43 mothers participated. 18 mothers in 2 SFBT groups (n = 9 in each group) received a 6-session SFBT group therapy while 25 mothers in a control group received no treatment. The Post-traumatic Growth Inventory was used to measure the PTG levels of the participants at baseline, post-treatment and 6-month follow-up assessments. Mothers who attended SFBT group-work reported higher PTG scores both at post-treatment (t = 4.065, p = 0.001) and 6-month follow-up (t = 2.980, p = 0.006) assessments. Further investigations to prove whether SFBT in groups can increase the positivity of clients would promote the use of SFBT.