When college students pronounce nonwords, their vowel pronunciations may be affected not only by the consonant that follows the vowel, the coda, but also by the preceding consonant, the onset. We presented the nonwords used by Treiman and colleagues in their 2003 study to a total of 94 first graders, third graders, fifth graders, and high school students to determine when these context influences emerge. According to some theories of reading development, early decoding is characterized by context-free links from graphemes to phonemes. However, we found that even children reading at the first-grade level (6-year-olds) were influenced to some extent by a vowel's context. The effect of context on vowel pronunciation increased in strength up to around the fifth-grade reading level (8- and 9-year-olds), and sensitivity to coda-to-vowel associations emerged no earlier than did sensitivity to onset-to-vowel associations. A connectionist model of reading reproduced this general pattern of increasing context effects as a function of training.