Inclusion Criteria:  between 11-18 years old; a clinical diagnosis of autism spectrum disorders according the DSM 5 as diagnosed by a BIG registered healthcare professional; insufficient emotion regulation after regular therapy for at least 1,5 years as indicated by a score above clinical cut-off (T-score = 65) on the EDI; comorbidities are allowed except for those interfering with safety.  Exclusion Criteria:  unable to respond to questions (parents or adolescents); no access to an Internet connection; insufficient mastery of Dutch language in parents or adolescents; physically incapable to work with the horses; unstable medication use; total IQ equal to or below 80 on the WISC-III-R or WISC-V; allergic or phobic to horses; insufficient regulation to safely handle the horses; therapy with horses within the last two years.