Universal Design for Learning (UDL) has been shown to have benefits for students with disabilities. However, little is known about its potential to support literacy for students with intellectual and developmental disabilities (IDD). This qualitative study explored (a) to what extent students with IDD are able to use Udio, an online UDL literacy environment; and (b) how students with IDD experienced and perceived Udio. A grounded theory approach was used to analyze classroom observations, as well as teacher and student interviews. Electronic usage logs and student-produced discussions and projects were analyzed descriptively. Students independently navigated the environment and used embedded supports, including audio-assisted reading and sentence starters. In addition, findings indicate that age-relevant content, choice, and opportunities to socialize in online discussions were especially engaging for students. Further research is warranted to determine how UDL environments affect the literacy development of students with IDD.