Purpose To identify clinician-perceived barriers and facilitators to the delivery of outcome measurement and evidence-based treatment practices and integration of these practices in aphasia rehabilitation. Materials and methods Using a convergent mixed methods design, aphasia clinicians (n = 87) across care settings in the United States completed an online survey designed within the Theoretical Domains Framework (TDF). Participants responded to open-ended questions and rated Likert scale statements. Qualitative data were analyzed using content analysis and quantitative data were summarized using descriptive statistics. Results Factors related to the TDF domain of “environmental context and resources” (priority and productivity demands; characteristics of resources) were cited as primary barriers in 70% of qualitative responses for both outcome and treatment practices and were consistent with Likert rating statements. Facilitators were associated with TDF domains of “memory, attention, decision-making” (decision-making processes), “knowledge” (awareness of evidence) and “social influences” (client and caregiver preferences). Conclusions Organizational-level factors and the misalignment of the research evidence with clinical needs are barriers to delivering evidence-based care in aphasia rehabilitation. Theoretically informed strategies such as establishing organizational infrastructure for practice change, developing clinically relevant evidence through research-practice partnerships, and implementing algorithms to support clinical decision-making can address barriers and leverage facilitators.