Rare diseases are conditions with low prevalence in the population. Their rarity combined with the high cost of treatment present unique challenges for healthcare policy and funding. This scoping review aimed to compare the funding approaches for rare disease treatments across high-performing health systems in Australia, Singapore, South Korea, the United Kingdom, and the United States as well as to identify best practices and areas for future research. 18 published papers and grey literature are included in the study. Findings show that different financing modalities and various strategies are employed by countries to balance budgetary constraints and access to rare disease treatments. The study suggests that outcome-based risk-sharing agreements can be a practical solution for managing the financial strain of costly treatments.