Thomas Brunner (April 1821 – 22 April 1874) was an English-born surveyor and explorer remembered for his exploration of the West Coast of New Zealand's South Island.

Brunner was born in April 1821 in Oxford. When he was fifteen, he began to learn architecture and surveying. In 1841, he joined the New Zealand Company in its venture to establish a settlement in the north of the South Island of New Zealand, to be called Nelson. As well as working as an apprentice surveyor and laying sections and roads for the new settlement, he explored the interior, seeking pastoral land for a growing colony. In 1846 he undertook extensive journeys with Charles Heaphy and a Ngāti Tūmatakōkiri tohunga named Kehu towards and along the West Coast.

In December 1846, Brunner commenced an expedition, accompanied by four Māori including Kehu, which began from Nelson. The party travelled down the Buller River and along the West Coast reaching as far south as Tititira Head, near Lake Paringa before returning to Nelson via the Arahura River. This arduous journey, which at one stage saw one of his legs paralysed, took him 550 days. He received honours from the Royal Geographical Society and the Société de Géographie (French Geographic Society). He continued to work as a surveyor and in 1851 was appointed Government Surveyor. He surveyed the sites, which he and Heaphy had scouted on previous explorations, for what would become the towns of Westport and Greymouth. He retired in 1869 and died of a stroke on 22 April 1874.

Thomas Brunner was born in Oxford, England, in April 1821, and baptised four months later on 22 August. He was the oldest son of William Brunner, an Oxford attorney who was also the county coroner. He was of Swiss descent, his father's parents having emigrated to England at the time of the French Revolution. The Brunner family were active in the Oxford community, Thomas' parents raising him and his siblings to appreciate cultural and charitable activities. In 1836, at the age of fifteen, Brunner was apprenticed to an architect, Thomas Greenshields, to learn architecture and surveying. Over the next five years, he became proficient in both skills.

In 1841, Brunner's father put his son's name forward to the New Zealand Company, which was seeking prospective emigrants for its proposed settlement in the South Island of New Zealand. The company wanted to populate its new settlement with well educated young men of excellent character and with leadership potential. Furthermore, apprentice surveyors, at the time known as "improvers", were in particular demand and Brunner, aided by character references from his employer and other notable residents of Oxford, was duly selected to join the company. In addition to his work as an improver, he was to assist the settlement's principal surveyor, Frederick Tuckett.

Brunner joined a party of six other young improvers which left England on 27 April 1841 aboard the Whitby. During the voyage to New Zealand, the improvers received further instruction and were tested by having to prepare draft layouts for the new settlement, Brunner's plan being the best of these. On 18 September, the Whitby arrived at Port Nicholson, the New Zealand Company's first settlement. The approximate site for the new settlement had yet to be finalised; initially intended for Banks Peninsula, this location was vetoed by the Governor of New Zealand, William Hobson. Instead, it was to be located at the top of the South Island, at Tasman Bay / Te Tai-o-Aorere. Early the following month a convoy of the company's ships, with Brunner aboard one them, crossed the Cook Strait to Tasman Bay. After scouting the area for three weeks, a site adjacent a deep and sheltered natural harbour was identified as being suitable for the settlement.

For the next two years Brunner assisted in the laying out of the settlement, which was to be called Nelson. A drawback with the Nelson settlement was its lack of pasture and the colony began to appropriate more and more of the plains in the nearby Wairau Valley, much to the displeasure of local Māori. Several personnel of the company, including Arthur Wakefield, the senior official of the company in Nelson, were killed in the Wairau Affray in June 1843. The New Zealand Company was forced to look south for more farming land. Brunner was sent to scout the Motueka Valley but failed to penetrate far due to poor weather. From local Māori he heard of a large plain to the south and passed on his findings to Tuckett. In August 1843, Tuckett dispatched Brunner to confirm the reports. Brunner, accompanied by Kehu, a Māori he had befriended, was again defeated by poor weather.

Life in Nelson was hard for the colonists. The company had limited finances and tightened its expenditure which affected the salaries of its employees. In 1844, it had to halt its operations for a time. Although Nelson had 300 landowners, nearly two-thirds were absentee owners and only 80 actually lived in the town. Brunner lived at Riwaka, a nearby village, and, in addition to carrying out survey work along the Motueka River, helped in the design and building of houses in the area. He ended his service with the company in August 1844.