Phrynobatrachus krefftii is a species of frog in the family Phrynobatrachidae. It is endemic to the Usambara Mountains in Tanzania, including both the West and East Usambaras and the Magrotto ridge. The specific name krefftii honours Paul Krefft, a German herpetologist and physician who made several expeditions to Africa. Common names Krefft's river frog and Krefft's puddle frog have been coined for it.