Background Although individuals with acquired brain injury (ABI) may be vulnerable to cyberscams, the lack of existing measures documenting cybersafety behaviours in people with ABI limits our understanding of ABI-specific risk factors, the frequency of this problem, and the ability to evaluate evidence-based interventions. The CyberABIlity Scale was developed to assess vulnerability in people with ABI via self-rated statements and practical scam-identification tasks. This study aimed to develop and refine The CyberABIlity Scale through feedback from clinicians and people with ABI. Methods Scale feedback was collected via three rounds of clinician surveys (n = 14) using Delphi methods and two rounds of cognitive interviews with participants with ABI (n = 8). Following each round, feedback was quantitatively and qualitatively summarised, and revisions were made accordingly. Results Key revisions included removing 12 items deemed irrelevant. Instructions and rating scales were revised to improve clarity. Cognitive interviews identified 15 comprehension errors, with further revisions made to support response clarity for participants with ABI. Clinicians and participants with ABI endorsed the content and face validities of The CyberABIlity Scale . Conclusions Following further validation, The CyberABIlity Scale has the potential to be an effective screening measure for online vulnerability for people with ABI within clinical and research settings.