This study examined how maturation and the size of deviance affect the development of mismatch responses to Mandarin lexical tones by a multi-deviant oddball paradigm with both large deviant T1/T3 and small deviant T2/T3 pairs in newborns and 6-month-olds. The T1/T3 pair elicited a positive mismatch response (P-MMR) at birth but an adult-like mismatch negativity (MMN) at 6 months of age. For the T2/T3 pair, no significant MMR was seen in newborns, whereas a P-MMR was found when infants are 6 months old. Results suggest that the developmental trajectories of MMRs are dependent on the neural maturation and the discriminability of tonal changes.