Background: Effective implementation strategies to improve speech and language therapists' (SLTs) aphasia management practices are needed. Australian SLTs working in the acute setting have reported inconsistent implementation of post-stroke aphasia guideline recommendations. Therefore, implementation efforts to address these gaps are necessary. However, little is known about the effectiveness of behaviour-change strategies in SLTs providing acute aphasia management. Aims: This study designed and tested the feasibility, acceptability and potential effectiveness of a tailored implementation strategy to improve acute SLTs' uptake of evidence in two areas of practice--aphasia-friendly information provision; and collaborative goal setting. Methods & Procedures: A pilot cluster randomized controlled trial design was used (retrospective trial registration number ACTRN12618000170224). Four acute SLT teams were randomly assigned to receive either Intervention A (targeted at improving information provision) or Intervention B (targeted at improving collaborative goal setting), and were blinded to their allocation. Interventions were tailored to address known barriers and included a face-to-face workshop incorporating behaviour-change techniques. Outcomes addressed the research questions of feasibility (e.g., treatment fidelity and retention of participants), acceptability (e.g., post-study focus groups) and potential effectiveness (e.g., medical record audits and behaviour construct surveys). The quantitative data were recorded at baseline and 3-6-month follow-up, allowing for change scores to be calculated. Outcomes & Results: All four clusters completed the study, with 37 SLTs participating. The majority of participants were female (36/37 = 97.3%), entry-level clinicians (15/37 = 40.5%), with a mean age of 30 years. Medical record data from 107 patients were included (post-intervention n = 61; information provision intervention n = 36, goal-setting intervention n = 25). Overall, there was a significant improvement in the target behaviour for Intervention A (mean improvement 52.78%, p = 0.001), but a small non-significant change in the target behaviour for Intervention B (8.46%, p = 0.406). There were potentially significant changes seen in several, but not all, of the domains targeted by the interventions (e.g., Knowledge (p = 0.014), Beliefs about Capabilities (p = 0.032), and Environmental Context and Resources (p = 0.000) for Intervention A). Conclusions & Implications: This study showed that a tailored implementation intervention targeting acute SLTs' aphasia management practices was feasible to deliver and acceptable for most participants. In addition, the interventions were potentially effective, particularly for the information provision behaviour targeted by Intervention A. It was possible partially to explain the mechanisms of behaviour change that occurred during the study.