This scoping review aimed to systematically map the outcomes and assessment tools used in randomized controlled trials (RCTs) of surgical prehabilitation. The review included 76 RCTs focusing on unimodal or multimodal prehabilitation interventions (nutrition, exercise, psychological support) lasting at least 7 days in adults undergoing elective surgery. The outcomes were classified according to the International Society for Pharmacoeconomics and Outcomes Research (ISPOR) framework. The study found that there is substantial heterogeneity in the reporting of outcomes and assessment tools across surgical prehabilitation trials. A total of 50 different outcomes were identified, measured using 184 outcome assessment tools. Observer-reported outcomes were collected in 86% of trials, with hospital length of stay being the most common. Performance outcomes were reported in 80% of trials, most commonly as exercise capacity assessed by cardiopulmonary exercise testing. Clinician-reported outcomes were included in 78% of trials, frequently including postoperative complications with the Clavien–Dindo classification. Patient-reported outcomes were reported in 76% of trials, with health-related quality of life using the 36- or 12-Item Short Form Survey being the most prevalent. Biomarker outcomes were reported in 16% of trials, primarily using inflammatory markers assessed with C-reactive protein. The review highlights the need for a core outcome set to harmonize outcome reporting and facilitate meta-analyses, as well as the importance of standardized and validated outcome assessments.This scoping review aimed to systematically map the outcomes and assessment tools used in randomized controlled trials (RCTs) of surgical prehabilitation. The review included 76 RCTs focusing on unimodal or multimodal prehabilitation interventions (nutrition, exercise, psychological support) lasting at least 7 days in adults undergoing elective surgery. The outcomes were classified according to the International Society for Pharmacoeconomics and Outcomes Research (ISPOR) framework. The study found that there is substantial heterogeneity in the reporting of outcomes and assessment tools across surgical prehabilitation trials. A total of 50 different outcomes were identified, measured using 184 outcome assessment tools. Observer-reported outcomes were collected in 86% of trials, with hospital length of stay being the most common. Performance outcomes were reported in 80% of trials, most commonly as exercise capacity assessed by cardiopulmonary exercise testing. Clinician-reported outcomes were included in 78% of trials, frequently including postoperative complications with the Clavien–Dindo classification. Patient-reported outcomes were reported in 76% of trials, with health-related quality of life using the 36- or 12-Item Short Form Survey being the most prevalent. Biomarker outcomes were reported in 16% of trials, primarily using inflammatory markers assessed with C-reactive protein. The review highlights the need for a core outcome set to harmonize outcome reporting and facilitate meta-analyses, as well as the importance of standardized and validated outcome assessments.