This article is about Nikko the city; see Nikko (priest) for the founder of Nichiren Shoshu Buddhism.

Nikkō (日光市; -shi) is a city located in the mountains of Tochigi Prefecture, Japan. It is a popular destination for Japanese tourists, housing the mausoleum of famed shogun Tokugawa Ieyasu (Nikko Toshogu) and that of his grandson Iemitsu, as well as the Futarasan Jinja, a shrine which dates to the year 767. There are also many famous hot springs (onsen) in the area. The mountains west of the city are part of Nikko National Park and contain some of the country's most spectacular waterfalls and scenic trails.