Airway suctioning is an important health care intervention that can be associated with serious adverse effects. Given the risks involved with suctioning, it is important to ensure the clinical competence of health care professionals who perform it. A scoping review was conducted to identify the nature and extent of research related to the assessment of airway-suctioning competence for health care professionals working with adults. This included an examination of the assessment context, the type of suctioning and health care professionals being assessed, and the methods used to assess competence. Four scientific electronic databases (MEDLINE, EMBASE, CINAHL, and the Cochrane Library) were searched from inception to March 9, 2018. A gray literature search was also performed. Two reviewers independently screened articles and resources for inclusion, and data were extracted using a form created by the authors. Seventy full text articles and resources were screened for eligibility, with 36 included in the review. Endotracheal suctioning was the most common type, and intensive or critical care units were the primary setting of interest (28 of 36, 78%). Competence or a component of competence for nurses, nursing students, nursing assistants, or nurse technicians was specifically addressed in 97% (35 of 36) of the included articles and resources; 4 of 36 (11%) also included physical therapists, 1 of 36 (3%) included respiratory therapists, and 1 of 36 (3%) was aimed toward all clinicians who perform suctioning. Nine (25%) used questionnaire-based assessments, 11 (31%) used checklists, audit forms, or other observational tools, and 16 (44%) used both. Directed content analysis revealed 3 major themes: consistency across overarching evaluation frameworks, inconsistency across detailed components, and inconsistency in the evaluation or reporting of assessment tool measurement properties. Additional gaps in the literature included limited consideration of health care professionals beyond nursing, limited consideration of settings beyond intensive and critical care, a lack of tools to assess nasotracheal and orotracheal suctioning, and limited detail regarding assessment tool development.