Thirumullaivoyal is a western neighbourhood of Chennai the capital of the India state of Tamil Nadu, under Avadi City Municipal Corporation Limits. It is located in the Chennai Metropolitan Area in Thiruvallur district, 3 km (1.9 mi) from Avadi and 3 km (1.9 mi) from Ambattur O.T Bus depot. The neighbourhood is served by Thirumullaivoyal railway station and Annanur Railway Station. The region was historically part of Thondaimandalam, a region in Chola Empire during 9th century CE.

The place was originally called Mullaivanam, a forest, after which the suburb is named. The history of the suburb revolves around the Masilmaninathar temple. The place is also one of the five revenue firkas under the Avadi Taluk. The place is a pilgrimage location and also houses several other religious and natural tourist destinations.

In ancient times, the forest surrounding Thirumullaivoyal was occupied by two notorious tribesmen, Vaanan and Onan from the Kurumbar tribe. King Thondaiman, the then ruler of the land, wanted to put an end to their atrocities. All his attempts went futile and finally he decided to defeat them in war. He set out for the war with all his infantry and cavalry with elephants and chariots. En route to the war, they waded through a dense growth of Mullai plants (Jasmine climbers). The foot of the elephant on which he was mounted was entangled in the dense foliage. The king and his men, in an attempt to free the elephant from this mess, went on to cut the wild twines with their swords and daggers. Suddenly they noticed blood gushing out from the leaves and found a 'lingam' bleeding. Shocked, the king was in great distress that he has committed a sin. Seeking mercy and forgiveness from Shiva, he prayed to Him. Without any delay Shiva and Parvathi appeared before the king lest he indulge in causing self-inflicted injury out of grief. Shiva asked the King to build a temple for Him right there and promised that he would reside there as Masilamaniswara, Shiva who is as precious as a gem, but without stains ['maasu' - dirty or stain (caused by the profuse bleeding), 'ila' - without, 'mani' - gem]. It is believed that Shiva also promised to support him in destroying the Kurumbars by sending his holy steed, the Nandi bull. On his orders, the Nandi also gets ready to go and fight for the King. This is why the Nandi in this temple faces outwards, ready to leave for the battle on the orders of Shiva, whereas in all other Shiva temples, it faces inwards facing the sanctum.

The history of the region is obtained from the inscriptions from the Masilamninathar temple. It has inscriptions from the period of Chola and Pandya, as per which, it was located on the banks of a tributary of river Palar. The temple has inscriptions from the period of Medieval Cholas and has received various architectural additions during their regime. An inscription from the period of Uttama Chola (970-85 CE) recorded as AR 669 of 1904 indicates that Sembiyan Mahadevi, the mother of Uttama bought 9,300 kulis of land for 80 kalanju of gold from the Mahasabha of Ambattur and made a gift to the temple. This is the northernmost of temples where Sembiyan Mahadevi donated for the temple construction. There are also inscriptions from the regime of Parthivendravarman, a feudatory of Uttama Chola, which mentions the reconquest of the regions lost to Rashtrakutas during the Battle of Takkolam fought during 949 CE. Another inscription recorded as 677 and 678 of 1904 from the period of Rajendra I (1012–1044 CE) records gifts to the temple. There are other inscriptions from subsequent Chola kings like Kulothunga III (1178–1218 CE) and Rajaraja III (1216–1256 CE). There are inscriptions from Pandya king Jatavarman Sundara Pandyan I and from kings of Vijayanagara Empire like Harihara Raya II (1377–1404 CE), Harihara Raya II (1377–1404 CE) and Mallikarjuna Raya (1446–1465 CE). The large Nandi Bull statue is believed to have been built to commemorate the victory of king Thondaiman over two demon brothers.

Avadi is the state assembly constituency in Tamil Nadu, India, formed after constituency delimitation. The areas included are Poonamalle Taluk (partially), Pattabiram, Nemilicheri, Thirunindravur (TP), Tiruverkadu (TP) and Avadi (M). It is included in the Thiruvallur parliamentary constituency.