The authors report data from a longitudinal study of the reading development of children who were assessed in the years of their 8th, 11th, 14th, and 16th birthdays. They examine the evidence for Matthew effects in reading and vocabulary between ages 8 and 11 in groups of children identified with good and poor reading comprehension at 8 years. They also investigate evidence for Matthew effects in reading and vocabulary between 8 and 16 years, in the larger sample. The poor comprehenders showed reduced growth in vocabulary compared to the good comprehenders, but not in word reading or reading comprehension ability. They also obtained lower scores on measures of out-of-school literacy. Analyses of the whole sample revealed that initial levels of reading experience and reading comprehension predicted vocabulary at ages 11, 14, and 16 after controlling for general ability and vocabulary skills when aged 8. The authors discuss these findings in relation to the influence of reading on vocabulary development.