Rare diseases have a low prevalence within society, resulting in limited awareness and challenges with data availability for research. While rare disease registries offer valuable data, ensuring quality of the data is essential. This review explores key themes and influencing factors affecting data quality in rare disease registries. Studies were identified through a pre-defined search term across multiple databases and screened for recurring themes and terms. The findings indicate a growing emphasis on data quality and evolving perspectives on how it is defined and assessed through the years.