Purpose: This study examined the clinical practice, self-efficacy, and beliefs about assessing and treating written language among speech-language pathologists (SLPs) working with school-aged clients (aged 5-21 years) in school and non-school settings in the United States. Method: A survey was completed by a nationwide sample of 344 SLPs working with school-aged clients in the United States. Statistical analyses were conducted to determine differences between (a) SLPs' self-efficacy in assessing and treating spoken versus written language and (b) school-based and non-- school-based SLPs' clinical practice, self-efficacy, and beliefs about their roles with written language. Results: All respondents reported significantly lower rates of self-efficacy in assessing and treating written language compared to spoken language, and their self-efficacy had a significant, positive relationship with the amount of clinical time devoted to written language. School-based SLPs devoted a significantly lower percentage of clinical time to written language, had significantly lower self-efficacy in addressing written language, and had lower rates of agreement on statements about their roles and responsibilities with written language compared to non--school-based SLPs. These differences were not found with spoken language. The most prevalent written language needs on respondents' workloads were reported as written expression (69.3%) and reading comprehension (66%). Conclusions: School-based and non--school-based SLPs report different levels of clinical time devoted to written language, self-efficacy in addressing written language, and beliefs about their roles in addressing written language. There is a need to investigate the reasons for these differences and the potential impact of preservice and in-service training in ameliorating them.