Kalyanasundaresar Temple, Nallur, Hindu temple in Nallur, Tamil Nadu, India.

The Kalyanasundaresar Temple is a Dravidian-style Shiva temple in Nallur, built on an artificial hillock and classified as a Madakkoil. Its five-tiered Rajagopuram leads to a courtyard with a flagstaff, Nandi mandapa and the Saptasagaram tank outside the main entrance. The main lingam stands in an east-facing sanctum, with a second lingam behind it said to have been installed by sage Agastya.

Sambandar and Appar praised the temple in the 7th-century Tevaram. Its masonry and towers date to the 9th century, and inscriptions on the walls record the 10th-century Chola king Uttama Chola. A grant from the fifteenth year of Raja Raja Chola names the village Panchavanmahadevi chaturvedimanagalam. Later Chola, Hoysala and Vijayanagara rulers of the Sangama, Saluva and Tuluva dynasties left records of land, cattle, oil and cash gifts.

The Tevaram hymns of Sambandar and Appar, sung here since the 7th century, remain part of daily worship. Devotees receive the Sadari blessing, a practice otherwise found in Vishnu temples, because Shiva is held to have granted his feet to Appar here. The ruined madam of Amaraneethi Nayanar stands on the south-west bank of the tank outside the temple.

The temple lies 10 km from Kumbakonam, 6 km east of Thirukkarugavur and 30 km south of Thanjavur, on the Thanjavur-Kumbakonam road. Daily rituals run from 5:30 a.m. to 10 p.m. The Saptasagaram tank sits outside the main entrance, and the Kali shrine is in the third precinct basement, reached by steps.

The central deity idol displays five different colors at different times of day, which inspired the temple's alternate name Panchalingeswarar. This visual transformation is a phenomenon that visitors can witness by spending time at the temple throughout the day.