Thomas McDonnell NZC (c. 1832 – 8 November 1899) was a 19th-century New Zealand public servant, military leader and writer.

He tried his luck on the Victorian goldfields from 1853 to 1855, then returned to New Zealand where he obtained a post in the Native Land Purchase Department under Alfred Domett in Auckland.

After being paid eight months late, McDonnell resigned from that job and went sheepfarming in the Hawkes Bay with his brother William, only to be defrauded by a third party.

[2] McDonnell led a short and ruthless campaign against a number of Taranaki Māori villages, torching and destroying as he and his men went.

He received the New Zealand Cross on 31 March 1886, and published fragmented memoirs, as well as a fanciful Māori history of the wars.