Abstract: Writing skills are an important predictor of academic and professional success of language learners and represent a key capability for social participation. Writing is a complex neurodevelopmental process that encompasses many linguistic, motor, and cognitive skills, and all of these skills must be given sufficient attention to assess it. Impaired written language is considered one of the problems of specific learning disorders, and its identification is very important for creating an appropriate learning environment. The aim of this study is to investigate the effective components in writing assessment and the conceptual model of the writing skill assessment scale for students with writing disorders in the elementary school. This study was conducted as a qualitative research using focus group interviews. The research population included experts in the fields of psychology, education of children with special needs, linguistics, and experienced teachers. Purposeful sampling of the study population was selected and conducted for group interviews until data saturation by consecutively conducting focus groups. The number of research participants was 24 people who participated in 3 focus groups and in 90-120 minute sessions. Qualitative content analysis was used to analyze the focus group data. The results showed that the main components of the assessment of writing skills of students with writing disorders include transcription, parsing and combining letters, spelling words, spelling sentences and punctuation, logical sentences (correcting writing), combining sentences, writing stories, and writing structure, each of which has subcomponents. Based on the findings, a conceptual model of the writing skills assessment scale was developed that can be used as a practical basis in building the scale and educational intervention. It is hoped that the results of this study can be used by teachers, psychologists, parents, and researchers and take a step towards improving the education and assessment of students with writing disorders.