Brigadier General Sir Herbert Ernest Hart, KBE, CB, CMG, DSO, VD (13 October 1882 – 5 March 1968) was an officer in the New Zealand Military Forces who served during the Second Boer War and the First World War. He later served as the Administrator of Western Samoa and worked for the Imperial War Graves Commission.

Hart volunteered for the Ninth New Zealand South African Contingent, which was raised for service in South Africa during the Second Boer War. By the time the contingent arrived in South Africa, the war was largely over. He saw extensive action during the First World War as a volunteer with the New Zealand Expeditionary Force, first at Gallipoli and then on the Western Front. By the end of the war, he had advanced in rank to brigadier general, commanding a number of brigades in the New Zealand Division.

Trained as a lawyer before the war, Hart returned to New Zealand to resume his legal practice after his discharge from the New Zealand Expeditionary Force. He later served as Administrator of Western Samoa from 1931 to 1935 and was knighted for his services in this role. From 1936 to 1943, he worked in the Middle East for the Imperial War Graves Commission, a task made difficult by the outbreak of the Second World War and the subsequent fighting in the region. Following his retirement in late 1943, he became involved in Rotary International. He died at his home in Masterton on 5 March 1968.

Hart was born at Taratahi, a small community near Carterton in the Wairarapa region. His father, William, was a farm labourer and the grandson of John Hart, a three-time Premier of South Australia. One of four children, he was educated firstly at Dalefield School, and then Carterton School. After finishing his formal education he worked for his uncle, an auctioneer and land broker, while also studying bookkeeping.

In 1900, Hart's brother Walter travelled to South Africa for service with the Fourth Contingent in the Second Boer War. This inspired Hart to volunteer for the Eighth New Zealand South African Contingent, but his application was declined. However, he, along with another brother, George, successfully enlisted for the Ninth Contingent. The minimum age for volunteers was 20 and he falsified his age to enlist. By the time he reached South Africa in April 1902, the war was effectively over. He was discharged in July 1902 with the rank of lance sergeant but travelled to England instead of returning to New Zealand with the rest of the contingent.

Hart eventually returned to New Zealand in early 1903. Shortly after his return he married Minnie Renall, the daughter of a farmer. The couple would have four children, one of whom died in infancy. He resumed working at his uncle's business and eventually became a director of the company. However, rather than pursue bookkeeping as a career, he commenced legal studies. He qualified as a solicitor in 1907, becoming a partner in a Carterton practice which he had joined the previous year.

Hart was also active in the Volunteer Force. It was common practice in the Volunteer Force for the men of a unit to elect their officers although they were sometimes directed by their superiors to vote for certain candidates. Hart was duly elected a lieutenant in the Carterton Rifle Volunteers. When the Volunteer Force was abolished in 1910 and replaced with the Territorial Force, which was organised more like a conventional military, he chose to continue his service. He was well regarded by his superiors and was promoted to captain in 1911. When he was promoted to major the following year, he was the youngest officer with that rank in his battalion. He was serving with the 1st Battalion of the 17th (Ruahine) Regiment when the First World War broke out.

Following the outbreak of the First World War, Hart immediately volunteered for the New Zealand Expeditionary Force (NZEF), which was being raised for service in the war on Britain's behalf. He was appointed second in command of the Wellington Infantry Battalion, under Lieutenant Colonel William Malone. The battalion embarked from Wellington in October 1914 for Egypt, and upon arrival, was primarily engaged in training before it was deployed along the Suez Canal late in January 1915 to support Indian troops stationed to guard against a rumoured Turkish attack. Three weeks of sentry duty ensued for the battalion before returning to Cairo.