Rahu Stalam, Hindu temple in Tirunageswaram, India.

Rahu Stalam, also known as Tirunageswaram Naganathar Temple, is a Hindu temple complex in Tirunageswaram, Tamil Nadu, India. Its four gateway towers, or gopurams, mark the entrances; the tallest rises in stone with a plain grey base and upper storeys covered in small painted sculptures. Inside, the second precinct holds the shrine of Rahu in its north-eastern corner, and a hall with Nayak-style pillars carved with yalis leads toward the main shrine.

The temple is believed to have been built by the Chola king Aditya I in the 10th century AD, and later rulers modified it with their own additions. The ornamental entrance hall was built under the Nayak rulers Achuthappa Nayak (1560–1614) and Raghunatha Nayak (1600–34) by their minister Govinda Dikshitar. Renovation work on the western walls was carried out in 1929, and the temple's kudamuzhukku consecration was held on 24 October 2021.

The village name Tirunageswaram comes from the serpents (nagas) said to have worshipped Shiva here, and the temple is one of the nine Navagraha Stalas, the one linked to Rahu. Rahu sits in a separate shrine in the second precinct with his consorts Nagavalli and Nagananni, and the milk poured over him is said to turn blue as it flows down. A five-and-a-half-foot snake that draped itself on the Rahu image in February 1986 is kept in a glass case for visitors to see.

The temple complex sits on the main road from Kumbakonam to Karaikkal, about 7 kilometers (4 miles) outside the town. Visitors should observe traditional dress and are required to remove footwear before entering the inner areas.

During the milk offering over the Rahu figure, those present watch as the liquid takes on a blue tint while it runs over the surface. This phenomenon is often interpreted as a sign of divine presence and draws worshippers from distant regions.