Herbert W. Greenfield was a Canadian politician and farmer who served as the fourth premier of Alberta from 1921 until 1925. Born in Winchester, Hampshire, in England, he immigrated to Canada in his late twenties, settling first in Ontario and then in Alberta, where he farmed. He soon became involved in the United Farmers of Alberta (UFA), a farmers' lobby organization that was in the process of becoming a political party, and was elected as the organization's vice president. Greenfield did not run in the 1921 provincial election, the first provincial general election in which the UFA fielded candidates, but when the UFA won a majority in the Legislature in that election he was chosen by the UFA caucus to serve as Premier. Like most of the UFA caucus, Greenfield had no experience in government and he struggled in the position.

The 1921 Alberta general election was held on July 18, 1921, to elect members to the 5th Alberta Legislative Assembly. It was one of only five times that Alberta has changed governments.