There has been little published research literature that has focused on using siblings to teach their non-verbal siblings a manual sign to communicate using the mandmodel procedure. The mand- model procedure is a naturalistic teaching strategy which has been demonstrated to improve communication and social outcomes for children with disabilities. This study investigated sibling tutors teaching their sibling tutees to use the manual sign “more” to request a want or need. The four sibling tutees were between the ages of 25 and 26 months and their sibling tutors were between the ages of 9 and 14 years. A multiple probe design across subjects was used for this study. The mand-model procedure, the independent variable, was used by the sibling tutors to teach the sibling tutees the manual sign “more.” The effectiveness of the use of the manual sign “more” was the independent variable. All four of the sibling tutees were able to successfully learn the manual sign and used the sign across maintenance and generalization phases.