This study investigated the decolorization of Rhodamine B by the UV/Fe(III)-Oxalate and UV/Fe(III)-Penicillamine process under neutral pH. Fe(III)-Penicillamine complexes showed much higher photoactivity than that of Fe(III)-Oxalate complexes. The efficiency for decolorization of Rhodamine B at pH 5.0 was 59% and 88% in Fe(III)-Oxalate and Fe(III)-Penicillamine complexes aqueous solution after 60 min irradiation, respectively, whereas, 35% and 57% was achieved at pH 7.0. Compared to the Fe(III)/Oxalate system, the kinetic constants kapp (min-1) for Rhodamine B decolorization in Fe(III)/Penicillamine system increased 2.4 and 2.0 times at pH 5.0 and 7.0, respectively. According to the obtained results, it was quite reasonable to conclude that penicillamine should play a similar role in Fe(III)-Penicillamine aqueous solution as oxalate did in Fe(III)-Oxalate solution. The results obtained indicated that the UV/Fe(III)-Penicillamine process was probably an alternative method to treat dye pollutant at neutral pH condition.