The morphology of frogs is unique among amphibians. Compared with the other amphibians, like salamanders, frogs are unusual because they lack tails as adults and their legs are used for jumping rather than walking.

Like all amphibians, oxygen can pass through the frog's highly permeable skin. This unique feature allows frogs to "breathe" through their skin. Oxygen is dissolved in an watery film on the skin and passes from there to the blood, so the frog's skin must remain moist at all times. Because of this, frogs are susceptible to many toxins in the environment, some of which can similarly dissolve in the layer of water and be passed into their bloodstream.

Adult frogs are characterized by long hind legs, a short body, webbed digits, protruding eyes, and the absence of a tail. Most frogs have a semi-aquatic lifestyle, but move easily on land by jumping or climbing. They typically lay their eggs in puddles, ponds or lakes, and their larvae, called tadpoles, have gills and develop in water. Adult frogs follow a carnivorous diet, mostly of arthropods, annelids and gastropods. Frogs are most recognized by their call, which is heard during the night or day, mainly in their mating season.

The structure of the feet and legs varies greatly among frog species, depending on whether they live primarily on the ground, in water, in trees, or in burrows. Frogs must be able to move quickly through their environment to catch prey and escape predators. Their unique adaptations, like webbed feet, toe pads, and camouflage are their survival tools. Some frogs even possess mild toxins, and a few, like the Poison Dart Frog, are especially toxic.