Publicly available health information is increasingly important for patients and their families. While the average US citizen reads at an 8 -grade level, electronic educational materials for patients and families are often advanced. We assessed the quality and readability of publicly available resources regarding hypoplastic left heart syndrome (HLHS). We queried four search engines for "hypoplastic left heart syndrome", "HLHS", and "hypoplastic left ventricle". The top 30 websites from searches on Google, Yahoo!, Bing, and Dogpile were combined into a single list. Duplicates, commercial websites, physician-oriented resources, disability websites, and broken links were removed. Websites were graded for accountability, content, interactivity, and structure using a two-reviewer system. Nonparametric analysis of variance was performed. Fifty-two websites were analysed. Inter-rater agreement was high (Kappa = 0.874). Website types included 35 hospital/healthcare organisation (67.3%), 12 open access (23.1%), 4 governmental agency (7.7%), and 1 professional medical society (1.9%). Median total score was 19 of 39 (interquartile range = 15.8-25.3): accountability 5.5 of 17 (interquartile range = 2.0-9.3), content 8 of 12 (interquartile range = 6.4-10.0), interactivity 2 of 6 (interquartile range = 2.0-3.0), and structure 3 of 4 (interquartile range = 2.8-4.0). Accountability was low with 32.7% (n = 17) of sites disclosing authorship and 26.9% (n = 14) citing sources. Forty-two percent (n = 22) of websites were available in Spanish. Total score varied by website type (p = 0.03), with open access sites scoring highest (median = 26.5; interquartile range = 20.5-28.6) and hospital/healthcare organisation websites scoring lowest (median = 17.5; interquartile range = 13.5-21.5). Score differences were driven by differences in accountability (p = 0.001) - content scores were similar between groups (p = 0.25). Overall readability was low, with median Flesch-Kincaid Grade Level of 11 grade (interquartile range = 10 -12 grade). Our evaluation of popular websites about HLHS identifies multiple opportunities for improvement, including increasing accountability by disclosing authorship and citing sources, enhancing readability by providing material that is understandable to readers with the full spectrum of educational background, and providing information in languages besides English, all of which would enhance health equity.