Due to condensed development processes, expanding evidence and differences in healthcare system characteristics, many COVID-19 guidelines differ in their quality and treatment recommendations, which has consequences for clinical practice. This review aimed to identify COVID-19 treatment guidelines, assess their quality, and summarise their recommendations. Guidelines were identified for five therapies most commonly used among inpatients with COVID-19 (remdesivir, dexamethasone, tocilizumab, baricitinib, and casirivimab/imdevimab) from 11 countries. Guideline quality was assessed using the Appraisal of Guidelines for Research and Evaluation II (AGREE-II) tool. Full details of recommendations and supporting evidence were analysed for high-quality guidelines, defined as those scoring ≥50% in Domain 3 (Rigour of Development) of AGREE-II. Overall, guidelines differed substantially in their quality and, even among high-quality guidelines using the same evidence, recommendations regarding specific therapeutics varied. Potential reasons for this heterogeneity, including the availability and consistency of clinical data, visibility of trial endpoints, and context-specific factors, are discussed