Background <p>We sought to examine key patient and provider perspectives to develop GUIDE (<i>Guiding participation toward Understanding, Inclusion, Diversity, and Equity for Cancer Clinical Trials)</i>, an intervention aimed&#xa0;to improve access to clinical trials through reimbursement of trial-related out-of-pocket costs and navigation. We sought patient and provider perspectives to optimize future GUIDE implementation.</p> Methods <p>Study team members conducted semi-structured 1:1 qualitative interviews with oncology patients (<i>n</i> = 20) and providers (<i>n</i> = 20) to identify influences on clinical trial participation and GUIDE acceptability, appropriateness, and feasibility. Data were analyzed using a deductive, rapid framework analysis. We applied a Consolidated Framework for Implementation Research and constructs of Proctor’s taxonomy of implementation outcomes to organize themes and inform the development of GUIDE.</p> Results <p>Patients reported clinical trial-related expenses as significant barriers for trial participation. Providers unanimously found GUIDE acceptable, appropriate, and feasible. Participants indicated program success would depend on establishing clarity around reimbursement and the role of the trial navigator (‘Guide’) within an existing multidisciplinary team and equipping the Guide with skills and affect to build trust with patients.</p> Conclusion <p>Health-related social needs (HRSN) are a critical influence on trial participation. Providers perceived the GUIDE program has potential to address HRSN and enhance trial diversity. For successful implementation, clear reimbursement protocols and infrastructure, integration of the Guide as part of the care team, and training for the Guide to screen for HRSN and connect patients to trial/institutional resources are needed.</p> Impact <p>We report patient and provider-identified elements critical for future trial navigator programs.</p>