A growing body of research has shown children on the autism spectrum are behind their peers developmentally in regard to their gross motor skill development. Given the increased risk for obesity and other health related co-occurring conditions associated with autism spectrum disorder, building foundational gross motor skills is vitally important so that individuals grow into physically active adults. However, the research on motor skill interventions for children on the autism spectrum is limited. Therefore, a multi-element multiple baseline across behaviors single subject design was employed to test the effectiveness of a motor intervention based on task modifications developed based on Dynamic Systems Theory. Using a purposive sample of two boys, aged 7 and 8 years, on the autism spectrum, task modifications were evaluated to understand the impact on the child’s motor performance and their performance’s persistence across two skills (i.e., horizontal jump and two-hand strike; P1[jump-pre]= 3; P1[strike-pre]= 4; P2[jump-pre]= 2; P2[strike-pre]= 2). As a result of the task modifications, both boys scores increased according to developed skill criterion and the raw scores of the Test of Gross Motor Development, 3rd Edition (Ulrich, 2018; P1[jump-post]= 6; P1[strike-post]= 6; P2[jump-post]= 6; P2[strike-post]= 8). Once the modifications were faded, both boy’s two-hand strike performance persisted; however, one boy’s horizontal jump performance returned to baseline levels. Yet, for this still there remained a high level of non-overlap (90.5%). This study demonstrates the potential impact that an intervention designed around task modifications can have; however, it also shows that interventions may need to be designed at an individual level and contain the flexibility to adjust to the needs of the child.