To describe process evaluation findings of a clinical trial to evaluate the Individualized Reduction of Falls (iROLL) program, a 6-session, group-based intervention designed to reduce fall incidence among people living with multiple sclerosis (MS) who use a wheelchair or scooter full-time. A mixed-methods process evaluation focusing on implementation and mechanisms of impact (MOI) was conducted. Both iROLL participants and trainers (licensed occupational or physical therapists) provided input. Seventeen iROLL participants and nine trainers participated. The overall session attendance rate was 93%. Content and logistics fidelity were 95% and 90%, respectively and average overall participant satisfaction rating was 4.7/5.0. Five MOI themes emerged: group dynamic, comprehensive nature of the program, strong program development, role of a skilled interventionist, and motivated participants. Recruitment challenged program reach. iROLL is acceptable to the target audience, can be delivered with high fidelity and has diverse and interacting mechanisms of impact operating. Remote delivery may improve reach. Effective iROLL delivery requires trainers with strong group management skills who can also individualize material while maintaining program fidelity. Comprehensive training and on-going support of the occupational and physical therapists delivering iROLL bolsters program effectiveness. Program access may improve with online delivery.