William Greening was an English-born American member of the Wisconsin State Assembly.
Greening was born in December 1827 in what was then Devonshire, England. He settled in La Grange, Walworth County, Wisconsin in 1855.
Greening was a member of the Assembly during the 1877 session. Other positions he held include Chairman (similar to Mayor), Supervisor and Assessor of La Grange. He was a Republican.