A modular ride-on is provided that is adjustable based on the needs of the operator. The modular ride-on offers children and young adults with disabilities a higher degree of freedom and comfort over traditional mobility devices—such as wheelchairs. The modular ride-on includes a chassis configured to removably couple a plurality of adjustable modules. The independently adjustable modules include a front-end module, first and second drive modules, a seating module, a harness module, an armrest module, a footrest module, a leg support, module, a body module, and a control module.