What is the Doctor's home planet?

The Doctor’s home planet is Gallifrey. It is the distant world inhabited by the Time Lords, the technologically advanced species to which the Doctor belongs.

Gallifrey is located in the constellation of Kasterborous and is commonly associated with the Time Lord capital, the Citadel. Its inhabitants study time travel and travel through history using TARDISes, machines whose interiors are far larger than their exteriors. The Doctor was trained at the Time Lord Academy before leaving Gallifrey and beginning a life of exploration.

A common mix-up is Skaro, which is the home planet of the Daleks, not the Doctor. Earth and Mars are important settings in Doctor Who, but neither is the Doctor’s birthplace. Gallifrey’s fate also became central to the programme’s mythology: it was believed destroyed during the Last Great Time War between the Time Lords and Daleks.

Later stories complicated that history, revealing that Gallifrey’s survival and hidden history were more mysterious than the Doctor had long believed. Even when the Doctor lives away from it, Gallifrey remains the defining home of their people.