Background: Social media is increasingly used by young people, including those with communication disability. To date, though, little is known about how speech-language therapists (SLTs) support the social media use of young people with communication disability. Aims: To explore what services SLTs provide to facilitate the social media use of young people with communication disability, including what these services look like, and the factors that impact SLTs' professional practices. Methods & Procedures: A sequential mixed methods approach was employed including an online survey and in-depth semi-structured interviews. Participants were qualified practising SLTs in Australia with a caseload that included clients aged 12-16 years. Quantitative data were analysed with SPSS. A thematic analysis of qualitative data was conducted with NVivo. Outcomes & Results: Survey responses from 61 SLTs were analysed. Interviews were conducted with 16 participants. Survey data indicated that SLTs do not systematically assess or treat young people's use of social media as part of their professional practice. Interview data revealed that where SLTs do support young people's use of social media, they transfer knowledge and practices typically used in offline contexts to underpin their work supporting clients' use of social media. In terms of factors that affect SLTs' practices, three major themes were identified: client/family factors, SLT factors, and societal factors. Conclusions & Implications: While young people with communication disability may desire digital participation in social media spaces, SLTs' current professional practices do not routinely address this need. Professional practice guidelines would support SLTs' practices in this area. Future research should seek the opinions of young people with communication disability regarding their use of social media, and the role of SLTs in facilitating this.