The developing use of a dictionary has the potential to provide self-teaching opportunities to improve reading, spelling and general phonological skills. Children's dictionary use was examined in two studies to find out patterns of use, skill and frequency of use and the relationships between these and reading, spelling and phonological development. In the first study 39 poor readers were compared with two groups of average readers, one consisting of 39 younger average readers of the same reading age and the other group of 31 average readers matched by age. In the second study 241 children (7-11 years) were divided on the basis of being above or below 9 years in age to examine developmental change. In both studies levels of non-verbal IQ were controlled between groups. Tests of reading vocabulary, spelling, non-word reading and speed and accuracy in looking up words in a dictionary were given. Examining dictionary skills in poor readers showed that they were significantly slower and less accurate in looking up words in a dictionary than their age peers who were average readers. Patterns of dictionary use varied with age with younger readers being three times more likely to give first preference to using a dictionary to look up spellings, whereas older reader expressed a preference that was much more evenly divided between checking spelling and looking up for meaning. Poor readers were much closer to their age peers in pattern of use. Self-rated frequency of dictionary use correlated significantly with spelling skill only in the younger readers. Persuading younger children to use a dictionary more could develop their spelling skills, possibly by encouraging them to be more proactive.