The Oral Motor Assessment Scale (OMAS) is a diagnostic tool used to assess the oral motor skills in individuals with neurological and neuromuscular disorders. This assessment was developed by Brazilian researchers and for the first time, its validity and reliability was examined in Brazil. The purpose of the present study was to examine the validity and reliability of the adopted Persian version of the OMAS (OMAS-P) to assess the oral skills of Iranian individuals with cerebral palsy (CP). In this non-experimental descriptive-analytical study 120 people (60 children and adolescents with CP) aged 3 to 15 years and 60 healthy subjects) participated. The research was carried out in number of stages including translation and adaptation of the OMAS to Persian (OMAS-P) in a forward-backward way. The oral motor skills functionality of the 120 people was examined using the OMAS-P. To assess the repeatability and reliability of the OMAS-P the assessments was repeated on the participants with CP disorder after two weeks. Results corresponding to this study indicated a reasonable agreement (Kappa >0.7) for all the OMAS-P items. The mean values of the OMAS-P items were appreciably different between the two groups (p < 0.001). The Persian version of the OMAS (OMAS-P) indicated consistent psychometric properties and can be used as a reliable tool for oral motor skills assessment in people with CP. However, it seems that by specifying factors such as the time frame for the OMAS, the position of the child during assessment, and whether or not parents use facilitating techniques, the comprehensiveness and efficiency of the OMAS data will also upgrade.