We studied the connection of IQ, reading disability (RD) and their interaction with reading, spelling and other cognitive skills in adolescents with average IQ and RD (n = 22), average IQ, non-RD (n = 71), below average IQ and RD (n = 29), and below average IQ non-RD (n = 33). IQ was not connected to reading and spelling in subjects without RD, but a connection to non-word spelling in subjects with RD existed. IQ and RD showed a connection to other cognitive skills (IQ to working memory, verbal memory and syntactic skills, RD to poor performance in text reading and rapid naming and both of them to reading comprehension, phonological and arithmetic skills), but no interaction existed. Our results are consistent with those of earlier studies showing that IQ does not play a significant role in the presentation of RD. However, adolescents with below average IQ and RD seemed to have much broader deficits in academically important skills such as arithmetic and reading comprehension than the other groups. (Contains 1 figure and 3 tables.)