Evidence-informed decision-making in health care relies on the translation of research results to everyday clinical practice. A fundamental requirement is that the validity of any healthcare intervention must be supported by the resultant favourable treatment outcome. Unfortunately, differences in study design and the outcome measures evaluated often make it challenging to synthesize the available research evidence required for secondary research analysis and guideline development. Core outcome sets (COS) are defined as an agreed standardized set of outcomes, which should be measured and reported as a minimum in all clinical trials on a specific topic. The benefits of COS include less heterogeneity, a reduction in the risk of reporting bias and ensuring all trials contribute data to facilitate meta-analyses; given the engagement of key stakeholders, it also increases the chances that clinically relevant outcomes are identified. The recognition of the need for COS for assessing endodontic treatment outcomes leads to the development of Core Outcome Sets for Endodontic Treatment modalities (COSET) protocol, which is registered (No. 1879) on the Core Outcome Measures in Effectiveness Trials (COMET) website. The objectives of this scoping review are to: (1) identify the outcomes assessed in studies evaluating surgical endodontic procedures; (2) report on the method of assessment used to measure the outcomes; (3) and assess selective reporting bias in the included studies. The data obtained will be used to inform the development of COS for surgical endodontics. A structured literature search of electronic databases and the grey literature was conducted to identify systematic reviews on periradicular surgery (PS), intentional replantation (IR) and tooth/root resection (RR), published between January 1990 and December 2020. Two independent reviewers were involved in the literature selection, data extraction and the appraisal of the studies identified. The type of intervention, outcomes measured, type of outcomes reported (clinician- or patient-reported), outcome measurement method and follow-up period were recorded using a standardized form. Twenty-six systematic reviews consisting of 19 studies for PS, three studies for IR and four studies for RR were selected for inclusion. Outcome measures identified for PS and IR included pain, swelling, mobility and tenderness, outcomes related to periodontal/soft tissue healing (including sinus tract), periradicular healing, tooth survival, life impact (including oral health-related quality of life), resource use and/or adverse effects. For RR, in addition to tooth survival, endodontic complications and adverse effects, the outcome measures were primarily periodontal-related, including pocket depth reduction, attachment gain, periodontal disease and periodontic-endodontic lesions. The majority of outcome measures for PS, IR and RR were assessed clinically, radiologically and/or via patient history. Specific tools such as rating scales (Visual Analog Scale, Verbal Rating Scale, Numerical Rating Scale and other scales) were used for the assessment of pain, swelling and tenderness, and validated questionnaires were used for the assessment of oral health-related quality of life. The range of follow-up periods was variable, dependent on the outcome measure and the type of intervention. Outcome measures, method of assessment and follow-up periods for PS, IR and RR were identified and categorized to help standardize the reporting of outcomes for future research studies. Additional outcome measures that were not reported, but may be considered in the COSET consensus process, include loss of root-end filling material, number of clinic visits, surgery-related dental anxiety and mucogingival aesthetic-related measures, such as scarring, black triangles, root surface exposure and tissue discoloration. COMET (No. 1879).