Background: In order to conduct research that is meaningful to speech and language therapy services and their patients, it is often desirable to conduct the research within routine clinical services. This can require considerable time and commitment from speech and language therapists (SLTs). It is therefore important to understand the impact that such participation in research can have. Aims To explore the impact of research participation in the Big CACTUS study of self-managed computerized aphasia therapy conducted in 21 UK NHS speech and language therapy departments. Methods & Procedures: An online survey was sent to SLTs who took the lead role for the study at their NHS Trust to evaluate the impact of study participation in three domains: capacity-building, research development and health services. The questionnaire, based on the VICTOR framework for evaluating research impact, included Likert scale statements and closed and open-ended questions. The results from open-ended questions were coded and analysed using framework analysis in NVivo 12 and the data from closed questions were analysed descriptively. Outcomes & Results: A total of 12 SLTs returned the survey. Nine codes were identified from open-ended questions and 20 predefined from the literature. Analysis of the responses demonstrated the perceived impact including improvements in practices and access to therapy, investments in infrastructure, increased SLT profile, and impact on research culture among SLTs. The usefulness of the intervention during the COVID-19 pandemic was also highlighted. Conclusions & Implications: The results suggest participation in Big CACTUS has resulted in improvements in patient care and SLT research capacity and culture in speech and language therapy departments.