Little is known about Internet resources for adolescent patients. This study assessed the quality, readability, and social reach of websites on an illustrative adolescent cancer diagnosis, osteosarcoma.The top 50 results from four queries in two search engines were screened. Quality and readability were determined using standard DISCERN tool, Flesch Reading Ease and Flesch–Kinkaid Grade. Social reach was gauged by social networking links, global website traffic, and a pilot adolescent-specificity measure.Of 400 websites assessed, 56 (14%) met inclusion criteria. Websites’ mean quality was fair (49.8 on 75-point scale; range 31.0–66.0, poor to excellent); 86% failed readability standards (Grade>8); 75% offered at least one social networking link; and 34% offered site-specific social media. More than 60% received over 50,000 visits in the past month. Only 12.5% included adolescent-specific content. Of the 10 websites ranked highest for quality, only one achieved both readability targets and adolescent-specific content.Although some patient-oriented websites on osteosarcoma are of acceptable quality, most failed readability targets, and few appeared to address adolescents.Better awareness of Internet health resources and social media for adolescents with cancer is needed to address gaps, promote health literacy and facilitate patient–provider communication.