Nellaiappar Temple is famous all over Tamil Nadu as the largest Shiva temple, steeped in tradition and also known for its sculptural splendours. The temple is situated in the centre of the city at a distance of two kilometres from the railway station. It is a twin temple dedicated to Goddess Parvathi and Lord Shiva. Even from a considerable distance, one can have a good view of the gopurams (towers). Both the gopurams were built according to the rules laid down in the agama sastras by Rama Pandyan. Rare jewels, the Golden Lily Tank, Musical Pillars, and the hall of a Thousand Pillars are worth seeing. The temple dates back to 700 AD and contains inscriptions which can be traced to be made around 950 A.D. It is believed there were two distinct temples, built separately for Shiva and Parvati, the consort to Lord Shiva, by the Pandyan kings. The Sangili Mandapam, a big terraced hall, linking these two was built in the 17th century. The towers also date back to the early 17th century. Vishnu and Agastya are believed to have worshipped Shiva here. There is also an interesting legend that there exists a tunnel behind the Ravana sculpture in the temple corridor that connects Tirunelveli and Madurai. This tunnel was supposed to have been used by the Pandya kings and their spies on secret missions.

The Nellaiappar temple car weighs approximately 400 tons and is the third largest temple car in Tamil Nadu. It is also said to be the largest human-powered car in South India. The car's axle was fabricated in steel during the British colonial period. Recently, steel rims were also used to reinforce the gigantic, yet aging wooden wheels. The Aani Car festival is the most popular festival associated with the temple, and the five cars (for Vinayakar, Murugan, Nellaiappar, Kanthimathi and Sandikaeswarar) by themselves are minor landmarks in the city.

Nindrasir Nedumaran (நின்றசீர் நெடுமாறன்), who reigned in the seventh century AD, contributed by constructing and renovating important parts in the temple. A beautiful garden founded in 1756, next to the mandapam, welcomes visitors with many colourful and fragrant flowers. The garden was designed by Thiruvengadakrishna Mudaliar. A square vasantha mandapam with 100 pillars is found in the midst of this garden.

The Nellaiappar Temple is bigger than the Madurai Meenakshi Amman Temple, though the latter is much more popular owing to its historical importance.