Sir Moses Haim Montefiore, 1st Baronet, FRS (24 October 1784 – 28 July 1885) was a British financier and banker, activist, philanthropist and Sheriff of London. Born to an Italian Sephardic Jewish family based in London, after he achieved success, he donated large sums of money to promote industry, business, economic development, education and health among the Jewish community in the Levant. He founded Mishkenot Sha'ananim in 1860, the first Jewish settlement outside the Old City of Jerusalem.

As President of the Board of Deputies of British Jews, he corresponded with Charles Henry Churchill, the British consul in Damascus, in 1841–42; his contributions are seen as pivotal to the development of Proto-Zionism. Queen Victoria's chaplain, Norman Macleod said of Montefiore: "No man living has done so much for his brethren in Palestine as Sir Moses Montefiore". He stated in an interview in the 1860s that "Palestine must belong to the Jews".

Moses Montefiore was born in Leghorn (Livorno in Italian), Tuscany, in 1784, to a Sephardic Jewish family based in Great Britain. His grandfather, Moses Vital (Haim) Montefiore, had emigrated from Livorno to London in the 1740s, but retained close contact with the town. It was known for making straw bonnets. Montefiore was born while his parents, Joseph Elias Montefiore and his young wife Rachel, the daughter of Abraham Mocatta, a powerful bullion broker in London, were in the town on a business journey. Moses was close to his aunt, Selina Hannah Laurence (née Montefiore 1768–1838); a visit to her in 1829 prompted his recollection of the death of his beloved grandmother Esther Hannah Montefiore (1733 – c. 1812). Selina lived at Bury Court, St Mary Axe, London, and had anglicised the surname of her husband Zaccaria Levy (1751–1828) to Laurence following his death.

The family returned to Kennington in London, where Montefiore attended school. His family's precarious financial situation prevented Montefiore from completing his schooling and he went out to work to help support the family. After working for a wholesale tea merchant and grocer, he was hired by a counting house in the City of London. In 1803 he entered the London Stock Exchange, but lost all of his clients' money in 1806 in a fraud perpetrated by Joseph Elkin Daniels. As a result, he probably had to sell or give up his broker's licence.

In 1812, Montefiore became a freemason, joining the Moira Lodge, No. 92 of the Premier Grand Lodge of England in London. From 1809 to 1814, Montefiore served in the Surrey Local Militia, rising to the rank of captain in the 3rd Surrey Local Militia's 7th Company. There was nothing unusual about Montefiore's militia career, and though not seeing active military service he did learn how to play the bugle. Montefiore was greatly disappointed when his company voted to disband on 22 February 1814. In 1815, he again bought a broker's licence, and briefly operated a joint venture with his brother Abraham until 1816. He largely closed down his trading activities in 1820.

In 1812, Moses Montefiore married Judith Cohen (1784–1862), daughter of Levy Barent Cohen. Her sister, Henriette (or Hannah) (1783–1850), married Nathan Mayer Rothschild (1777–1836), for whom Montefiore's firm acted as stockbrokers. Nathan Rothschild headed the family's banking business in Britain, and the two brothers-in-law became business partners. In business, Montefiore was an innovator, investing in the supply of piped gas for street lighting to European cities via the Imperial Continental Gas Association. In 1824 he was among the founding consortium of the Alliance Assurance Company (which later merged with Sun Insurance to form Sun Alliance).

Though somewhat lax in religious observance in his early life, after his visit to the Holy Land in 1827, Montefiore became a strictly observant Jew. He traveled with a personal shohet (ritual slaughterer), to ensure that he would have a ready supply of kosher meat. Although Montefiore spent only a few days in Jerusalem, the 1827 visit changed his life. He resolved to increase his religious observance and to attend synagogue on Shabbat, as well as Mondays and Thursdays when the Torah is read. The visit had been a "spiritual transforming event" for him.

In 1831, Montefiore purchased a country estate with twenty-four acres on the East Cliff of the fashionable seaside town of Ramsgate. The property had previously been a country house of Queen Caroline, when she was still Princess of Wales. It was next owned by the Marquess Wellesley, a brother of the Duke of Wellington. Soon afterward, Montefiore purchased the adjoining land and commissioned his cousin, architect David Mocatta, to design a private synagogue, known as the Montefiore Synagogue. It opened with a grand public ceremony in 1833.