Equine-assisted activities and therapies (EAAT) have been suggested to improve adaptive behavior, and possibly motor function, in autism spectrum disorder (ASD). This study investigated the effects of EAAT on adaptive behavior and motor function in 15 children with ASD (13 males) aged 7–15 years as well as the impact of EAAT on the magnitude of stress in the parent–child system and the evolution in the child interaction with both the trained therapist and the therapeutic animal through the 20 weekly sessions of EAAT. EAAT were associated with greater adaptive behavior and coordination (all p ≤ 0.01) as well as a progressive improvement in the child’s abilities to respond to the increasing complexity of such form of positive behavioral support (all p < 0.001). However, EAAT did not prove to be effective in reducing parental distress. Collectively, preliminary evidence presented here may have important public health implications and gives reason to hope that EAAT could possibly be an effective option in ASD, warranting further investigation of its potential benefits in clinical trials among larger samples.