Acute radiation dermatitis (ARD) is a common adverse effect experienced by patients undergoing radiation therapy. Effective assessment tools to accurately measure and manage ARD's impact on patients' quality of life and treatment outcomes is needed. The aim of this study was to evaluate the diverse tools and outcome measures used in the assessment of ARD. A systematic review of MEDLINE®, Embase, and Cochrane was conducted for records 1946-March 2024. A total of 423 studies, including 227 randomized controlled trials (RCTs), were included in the analysis. The review identified 58 distinct tools utilized in the assessment of ARD including clinician and patient-reported outcomes, quality-of-life instruments, and biophysical measures. The most frequently employed tools were the Radiation Therapy Oncology Group criteria, Common Terminology Criteria for Adverse Events, Skindex-16, Visual Analogue Scale, Dermatology Life Quality Index, European Organization for Research and Treatment of Cancer Quality of Life C30, Radiation-Induced Skin Reaction Assessment Scale, Skin Toxicity Assessment Tool, photography, reflectance spectrophotometry, and the corneometer. This investigation into ARD assessment tools reveals a broad application of instruments but is limited by a pervasive lack of consensus, preventing the endorsement of a standardized toolset. The variability in tool use necessitates further research, particularly high-quality RCTs, to establish validated and reliable measures. Future publications, including Delphi consensus-based recommendations, are anticipated to address these gaps, aiming to standardize ARD assessment methodologies.