Surgical subinternships are important rotations for students preparing for a career in general surgery; however, these rotations often vary by institution and service. This modified Delphi study was conducted to reach a consensus set of roles, responsibilities, and expectations of fourth-year medical students on their surgical subinternships. Candidate statements on roles, responsibilities, and expectations of subinterns were categorized into 7 domains: rotation structure, rounding and patient care, operating room conduct, technical skills, knowledge base, clinic, and professionalism. Expert panels were assembled of key stakeholders: program directors, clerkship directors, other education faculty, trainees, and recent subinterns. Three Delphi rounds were conducted from January to April 2023 to reach consensus defined a priori as a Cronbach α ≥ 0.8 and 80% or greater panel agreement. Forty-six expert panelists were recruited to participate in Delphi rounds, with 100%, 95.7%, and 97.8% response rates in the first, second, and third rounds, respectively. By the third round, 67 statements reached consensus as essential roles, responsibilities, and expectations of surgical subinterns. Key themes from these 67 statements included subinterns approximating the role of an intern with respect to work hours, patient care responsibilities, basic technical skills, and knowledge base. Panelists rated rounding and patient care as the most important domain, followed closely by professionalism. Additional key domains for evaluation in descending order were knowledge base, operating room conduct, clinic, and technical skills. By the third round, notable disagreements in the Delphi process included technical skills and rounding and patient care (93.3% and 88.9% agreement, respectively). This study provides a national consensus on core roles, responsibilities, and expectations for medical students completing surgical subinternships. Students can use these recommendations to prepare for subinternships, whereas faculty as well as residents and fellows can use them to evaluate applicants for general surgery residency positions.