Objective: This study aimed to assess the quality and readability of web-based information on familial hypercholesterolaemia. Design, setting and methods: Internet searches using the terms 'familial hypercholesterolemia', 'hypercholesterolemia', 'inherited high cholesterol', 'hereditary high cholesterol' and 'inherited high LDL' were conducted with the Google, Yahoo! and Bing search engines using default settings during August 2021. The first 50 web links that appeared using each search engine were evaluated using the Flesch Reading Ease Score (FRES) and DISCERN instrument for readability and the quality of the website. The LIDA tool was used to assess reliability and usability. Results: In all, 750 websites were accessed and 38 websites were included in the analysis. The majority of the websites (29, 76.3%) were owned by non-governmental institutions. Twelve (30.8%) websites were certified by the Health On the Net Foundation (HON) code of conduct. Only 17 websites (44.7%) had a stated author. Twenty-nine (76.3%) websites had a stated date of publication. Only 16 (42.1%) provided references for the statements made. Infographics were used in 17 (44.7%) websites. The median FRES was 47.15 (range: 22.3-91.8), which is equivalent to college-level readability. The median LIDA usability and reliability score was 38.00 (range: 25-46) and 15.00 (range: 7-24), respectively. The median DISCERN score was 45.00 (range: 17-76). The DISCERN score was significantly associated with the FRES (0.047) and whether the website was governmental or not (0.028). Conclusion: According to this study, the readability, reliability, usability and quality of the majority of websites were inadequate. Due to the rapid growth in the use of the Internet, steps need to be taken to standardise and regulate patient education websites for this and perhaps other health conditions.