Wesley Township is located in Will County, Illinois. As of the 2010 census, its population was 2,241 and it contained 891 housing units. Wesley Township was formed from the south-eastern part of Wilmington Township in 1846. It contains the census-designated places of Ballou, Rest Haven, and Ritchie. Wesley, Illinois was the setting for a murder in the 1966 mystery fiction book "Deadline" by Thomas B. Dewey.
According to the 2010 census, the township has a total area of , of which (or 97.65%) is land and (or 2.35%) is water.