Janaki Mandir is a Hindu temple in Janakpur in the Mithila region of Nepal, dedicated to the Hindu goddess Sita.
It is an example of Hindu-Koiri Nepali architecture. It is often considered the most important model of Koiri architecture in Nepal. Fully built in bright white and constructed in an area of 4,860 sq. feet in a mixed style of Mughal and Koiri domes, the temple is 50 meters high. It is a three-storied structure made entirely of stone and marble. All its 60 rooms are decorated with the flag of Nepal, colored glass, engravings and paintings, with beautiful lattice windows and turrets. According to legends and epics, King Janak ruled this area (called Videha) during the Ramayana period. His daughter Janaki (Sita), during her swyambar, had chosen Lord Rama as her husband, and become queen of Ayodhya. Their marriage ceremony had occurred in the nearby temple.
The temple is popularly known as the Nau Lakha Mandir (meaning "nine lakhs"). The cost for the construction of the temple was about the same amount of money: rupees nine lakhs or nine hundred thousand, hence the name. Queen Vrisha Bhanu of Tikamgarh, India built the temple in 1910 AD.
In 1657, a golden statue of the Goddess Sita was found at the very spot, and Sita is said to have lived there. The legend said it that it was built on the holy site where Sannyasi Shurkishordas had found the images of Goddess Sita. In fact, Shurkishordas was the founder of modern Janakpur and the great saint and poet who preached about the Sita Upasana (also called Sita Upanishad) philosophy. Legend has claimed it that King Janak(Seeradhwaj) performed the worship of Shiva-Dhanus on this site.
As of 26 April 2015, the temple is reported to have partly collapsed from the earthquake in April 2015.