This article lists the longest church buildings in the world as measured by various criteria.
This includes all cathedrals (the seat of a bishop), basilicas, and other types of churches.
It does not include temples of other religions, e.g. mosques, synagogues.
It does include at least one building, Hagia Sophia, which was built as a church but currently operates as a mosque.
Note: this list is incomplete e.g. St. Mary's Cathedral, Sydney is 107 metres long (ref.