BackgroundImpairments in cognition significantly affect patient functioning and rehabilitation outcomes. Assessment is essential to identifying at‐risk individuals and guiding care plans.ObjectiveA cognitive assessment protocol was implemented in occupational therapy (OT) and speech‐language pathology (SLP) outpatient practice. Using the Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE‐AIM) framework and Theoretical Domains Framework (TDF), this study (1) measured the reach and adoption of the cognitive assessment protocol and (2) explored determinants and strategies that may affect adoption.DesignSequential mixed methods.SettingTwo outpatient rehabilitation clinics (A and B) within a health care network.ParticipantsMedical records from 220 adult patients with neurologic diagnosis and 15 OT and SLP clinicians.InterventionsCognitive assessment protocol.Main Outcome Measure(s)Reach of the assessment protocol across patient characteristics and adoption across clinical sites were measured quantitatively via retrospective electronic medical records review. Qualitative data on effectiveness and the implementation process were collected via clinician focus groups.ResultsProtocol adoption rates were 71% and 54% at clinics A and B, respectively. Site B OT was more likely to be noncompliant with protocol adoption compared to Site A, when controlling for patient characteristics, (81% vs. 16%, respectively; odds ratio = 11.4, 95% confidence interval [3.36–38.64], p ≤ .001). Patient age was a significant factor for protocol reach; older age was associated with noncompliance of the SLP protocol adoption, p < .05. Both sites employed implementation strategies targeting the provider level (eg, education/training); Site A additionally included organization‐level strategies (eg, leadership engagement). In the absence of organization‐level strategies, OT and SLP clinicians at Site B identified barriers related to leadership support, resources, and workflow.ConclusionsStandardized practice protocols are feasible to implement within the rehabilitation setting, though multilevel implementation strategies may be needed to promote adoption. Aligning practices with the needs, values and priorities of the organization, providers, and patients and families is imperative.