Reading instruction can direct attention to different unit sizes in print-to-speech mapping, ranging from grapheme-phoneme to whole-word relationships. Thus, attentional focus during learning might influence brain mechanisms recruited during reading, as indexed by the N170 response to visual words. To test this, two groups of adults were trained to read an artificial script under instructions directing attention to grapheme-phoneme versus whole-word associations. N170 responses were subsequently contrasted within an active reading task. Grapheme-phoneme focus drove a left-lateralized N170 response relative to the right-lateralized N170 under whole-word focus. These findings suggest a key role for attentional focus in early reading acquisition.