Dyslexia is characterized by poor word reading. In research, education, and diagnosis, "oral" reading is commonly assessed, and outcomes are generalized to "silent" reading, although similarities and differences between oral and silent reading are poorly understood. We therefore compared oral word reading, oral text reading and silent text reading. Children (n = 40; aged 8-11) and adolescents (n = 54; aged 14-18) with dyslexia, and typical readers (n = 18, and n = 24 respectively), read a word-list and an age-appropriate text aloud, and silently read a text including instructions for simple tasks. Whereas oral and silent reading fluency were comparable for children, silent reading was more fluent than oral reading for adolescents. Importantly, the silent reading deficit of children and adolescents with dyslexia was as large as in oral reading or larger, highlighting the need for a focus on both reading modes in research, diagnosis and treatment of dyslexia.