Photometric redshifts have been determined for the galaxies in the Hubble Deep Field. The resulting redshift distribution shows two peaks: one at z~.5 and one at z~2.5. Luminosity functions derived from the redshifts show strong luminosity evolution as a function of redshift. This evolution is consistent with the Babul & Rees (1992) scenario wherein massive galaxies form stars at high redshift while star formation in dwarf galaxies is delayed until after z=1.