Slow maturation of visual pathways transmitting low spatial frequency (LSF) information may contribute to inaccurate facial emotion recognition in adolescence. We recorded ERPs from adolescents and adults to upright and inverted happy faces, fearful faces, and chairs, which were unfiltered, contained only LSFs, or only high spatial frequencies. P100s and N170s were larger for adolescents than adults, with the greatest effect size for LSF stimuli. For LSFs only, adolescents showed a larger N170 inversion effect for happy than for fearful faces, but adults showed the opposite response. Thus, immaturities in LSF pathways appear to impact facial expression processing in adolescents.