Benjamin Yate Ashwell was an Anglican missionary and a member of the Church Missionary Society mission in New Zealand in the 19th century. He was missionary to the Māori in the western Waikato region. In 1839 he was sent to Kaitotehe, near Mount Taupiri, where he established the Kaitotehe Mission, with branch missions at Te Awamutu and Otawhao in the valley of the Waipa River.
Ashwell and his wife arrived in Paihia on 23 December 1835. He worked as a catechist among the Europeans at Kororāreka. In l838 the Revd. Robert Maunsell and Ashwell set up a mission station and a school at Port Waikato among the Ngāti Tāhinga. In 1839 he was sent to Kaitotehe, near Mount Taupiri, where he established the Kaitotehe Mission, with branch missions at Te Awamutu and Otawhao in the valley of the Waipa River. He remained at that mission into the 1840s. He was ordained in December 1848 after attending St John's College, Auckland. In 1846 he was asked to settled a dispute at Rotokauri between 2 hapū of the Waikato Tainui – the Ngāti Hine and the Ngāti Pou – respecting the right to take eels from a certain channel. He was appointed as a deacon on 24 December 1848 after attending St John's College, Auckland. He was ordained as a priest on 22 May 1853. From April to June 1860 Ashwell travelled on the schoonerSouthern Cross with the Rev. J.C. Patteson to visit the Melanesian Mission stations in the Loyalty Islands, New Hebrides, and Banks Islands. On 23 June 1860 while returning from Melanesia to New Zealand, the Southern Cross was wreaked in a storm near Ngunguru, Northland, without loss of life. In the early 1860s, Ashwell opposed the Māori King Movement, which was a means of attaining Māori unity to halt the alienation of land at a time of rapid population growth by European colonists. In July 1863, Ashwell moved to Auckland following the Invasion of the Waikato by the colonial government forces who were sent to crush the Māori King Movement. Ashwell returned to Kaitotehe Mission at the end of 1864, however the war in the Waikato had scattered the Māori people who had supported the mission. He worked to re-establish the mission until the end of the 1860s, when he retired from missionary work to engage in church administration. On 26 April 1883 he retired from the CMS. Ashwell died on 29 September 1883 at Remuera, Auckland.