Internet usage for obtaining health-related information is widely popular among patients. However, there are still concerns about the reliability and comprehensibility of online information. The purpose of this study is to investigate the reliability and readability of osteoporosis-related websites.On April 2, 2020, we searched the term "osteoporosis" on Google (https://www.google.com). We evaluated the first 200 uniform resource locators (URLs) in the query results regarding typology, the scores, Health on the Net Foundation Code of conduct (HONcode) certification, Flesch-Kincaid Grade (FKG), and Simple Measure of Gobbledygook (SMOG) scores. The scoring system and HONcode stamp were used for assessing the reliability, whereas FKG and SMOG scores were used to assess the readability of online information.Of the 151 analyzed websites, 57 (37.7%) were classified as highly reliable, and 19 (12.6%) were assigned with HONcode certification. The average FKG scores (8.81 ± 2.21) and SMOG scores (7.63 ± 1.81) were below the recommended grade, which is considered as easily readable. High reliable information was found to have higher readability scores, thereby representing the difficulty of readability. We observed a weak correlation between the increased reliability of information and decreased readability.Osteoporosis-related content on the internet generally has low reliability. High-reliable information is available online in scientific published materials, health portals, and news. Although the readability of the overall material is acceptable, the high-reliable websites still require high literacy and comprehension skills.