Melanophryniscus klappenbachi (common name: Klappenbach's red-bellied frog) is a species of toad in the family Bufonidae. It is found in the Gran Chaco in northern Argentina, Paraguay, and Brazil (Mato Grosso do Sul), and possibly in Bolivia. Its specific name refers to Miguel Angel Klappenbach, a Uruguayan zoologist.
Melanophryniscus klappenbachi is a common species facing no significant threats. It is present in the international pet trade.