A house gecko is a type of small lizard that gained its name because it adapts easily to living with people and often is found in houses in the countries in which it lives. It belongs to the gekkonidae family, which includes more than 2,000 species of geckos. House geckos are part of the genus Hemidactylus and there are dozens of species of house geckos; it is the second most populous genus in the gekkonidae family. House geckos are found throughout the tropics and in many subtropical parts of the world.

House geckos are noted for their ability to colonize, traveling on cargo ships and ocean flotsam to different areas. Common characteristics of house geckos include vertical eyes with no eyelids — instead they have a film over their eyes to protect them. They have toes and feet made for climbing and are even able to walk vertically up walls. Like many gecko species, house geckos can detach their tails to escape from prey, and the tails will continue to move unpredictably as a distraction.

One of the most popular species of house gecko, often found in pet stores, is Hemidactylus frenatus, or the common house gecko. This species of house gecko comes originally from Southeast Asia and has been introduced in the wild into Australia, Mexico, eastern Africa, New Guinea and elsewhere. It sometimes is called the Pacific house gecko or Asian house gecko.

This species of house gecko can grow from 3 to 5 inches long (approximately 7.5 to 13 cm) and can live as long as five years. It is a gentle lizard but also fast-moving and hardy. Its skin can change color according to its mood and sometimes can even appear transparent. The common house gecko also is an excellent climber that can scale vertical surfaces and, when in captivity, it can climb upside down across the top of its cage.

Some of the other species of house geckos include the Mediterranean house gecko, or Hemidactylus turcicus; the tropical house gecko, or Hemidactylus mabouia; and Brook's house gecko, or Hemidactylus brookii. The Mediterranean house gecko, also called the Turkish gecko, is native to Europe, but it has spread throughout the world. The tropical house gecko is native to tropical Africa but is also found in the Americas and the Caribbean. Brook's house gecko is a widespread species found in Africa, India, Mexico and many other places.