Thiruvalla, (Malayalam: [t̪iɾuʋɐlːɐ]) also spelled Tiruvalla, is a municipality in Pathanamthitta district, Kerala, India. The town is spread over an area of 27.15 km² (10.48 sq mi) and has a population of 52,883 people, down from 56,837 in 2001. It is also the Headquarters Of Thiruvalla Revenue Division. It lies on the northern banks of the Manimala River, in a land-locked region surrounded by irrigating canals and rivers. It is the largest town in the district, and is a major financial, educational, healthcare, cultural, and commercial centre in central Travancore. It is also called The Healthcare City & Banking Capital Of Kerala. Thiruvalla Taluk has a land area Of 154 km² (59 sq mi).

Thiruvalla is also known as the "Town of Non-Resident Indians", as a large portion of its inhabitants form a part of the Malayali diaspora. Though Thiruvalla struggles with an aging and declining population and experiences a high emigration rate, in recent years the town has experienced growth in its economy and urban revitalisation.^{[citation needed]}

There are two theories as to the origin of the name "Thiruvalla".

According to tradition, the name Thiruvalla comes from the word "Valla Vaay", named after the river Manimala which used to be known as Vallayār. Before the development of proper roads, Thiruvalla developed at the mouth of the Vallayār, and connected various places through waterways, and hence was known as Valla vāy (with the word vāy meaning 'mouth of a river' in old Malayalam). Later, the Malayalam Prefix "Thiru" (used to signify something revered) was added, and thus became "Thiruvalla".

The second theory comes from the 10th-century Sanskrit work "śrīvallabha kṣētra māhātmyaṁ" (श्रीवल्लभ क्षेत्र माहात्म्यम्). It states that the name comes from one of the major temples in the town – the Sreevallabha Temple. The name Thiruvalla hence comes from the word "śrīvallabhapuraṁ", meaning "the town of Vallabha".

There is plenty of evidence to suggest that the area had been inhabited since 500 BCE, although an organized settlement was only founded around 800 CE. The present-day areas of Niranam, and Kadapra on the western part of Thiruvalla were submerged under the sea before then. It is one of the 64 ancient brahmana graamams.

Stone axes have been reported from Thiruvalla, belonging to Neolithic Age. Thiruvalla has many Neolithic remains and got civilized earlier. The Aryan culture presented Thiruvalla as one of the 64 Brahmin settlements of Kerala, and one of the important too. Ptolemy mentions the Baris river, the present "Pamba" river.

Thiruvalla was also an important commercial centre with the Niranam port in olden days, which is described by Pliny as "Nelcynda". At this light, the "Bacare" could have been modern "Purakkad". The fact that modern western Thiruvalla contains the coastal kind of sand, and several seashells in the soil despite being landlocked proves that prior to the reclamation of Kuttanad from sea, Niranam and the whole western Thiruvalla could have been a coastal area.