Experience-dependent plasticity in the mature visual system is considered exclusively cortical. Using chronic two-photon Ca2+ imaging, we found evidence against this tenet: dLGN cells showed robust ocular domi-nance shifts after monocular deprivation. Most, but not all responses of dLGN cell boutons in binocular visual cortex were monocular during baseline. Following deprivation, however, deprived-eye dominated boutons became responsive to the non-deprived eye. Thus, plasticity of dLGN neurons contributes to cortical ocular dominance shifts.