This study examined the impact of phonetic training on English lexical schwa vowel in primary school learners (aged 12) of English as a foreign language in Spain. Students’ perceptual awareness on the occurrence of weak vowels in unstressed position in English was tested in three groups: i) on one group which underwent auditory discrimination and identification practice, ii) on one group which underwent listen-and-repeat practice, iii) on one group with native exposure. The first two groups could consistently identify full vowels as incorrect in post-test. Few differences in perceptual awareness as a function of position of the unstressed vowel in the word (pre and post-tonic) were found. Word familiarity was found to affect pre-test performance but to be hindered after treatments. Results acknowledge the positive impact of controlled phonetic training on L2 sound perceptual awareness in classroom settings and contribute to the development of L2 pronunciation teaching and learning.