(Lionel) Walter Rothschild, 2nd Lord Rothschild (February 8, 1868 - August 27 1937) was a British banker and zoologist from the international Rothschild financial dynasty.
Educated at Magdalen College, Cambridge, from 1889 to 1908 he worked for the family firm of N. M. Rothschild and Sons, though his greatest passion was zoology, particularly the collecting and taxonomy of birds and butterflies. He participated in, and funded, expeditions across the world to gather specimens, and wrote numerous scientific papers.
Near his country home at Tring Park, he established his own private zoological museum in the town of Tring, which he opened to the public from 1892. It became one of the world's largest natural history collections, and in 1936 he gifted it to the Trustees of the British Museum. The Walter Rothschild Zoological Museum is now part of the Natural History Museum.
Walter Rothschild was Liberal and Liberal Unionist Member of Parliament for Aylesbury from 1899 to 1910. A notable eccentric, he kept kangaroos in his garden and harnessed a team of zebras to pull his carriage.
As an active Zionist and close friend of Chaim Weizmann he worked to formulate the draft declaration for a Jewish homeland in Palestine. On 2nd November, 1917 a letter from Arthur Balfour addressed to "Dear Lord Rothschild" at his London home in 148 Piccadilly set out the Balfour Declaration which committed the British Government to supporting the establishment in Palestine of a national home for the Jewish people.
Walter inherited the peerage from his father Nathaniel Mayer Rothschild in 1915. He had no children, and his younger brother Charles Rothschild had predeceased him, so the title was inherited by his nephew (Nathaniel Mayer) Victor Rothschild.