Udell Township is one of eighteen townships in Appanoose County, Iowa, United States. As of the 2010 census, its population was 343.
It was named for Dr. Nathan Udell, a pioneer settler.
Udell Township covers an area of and contains two incorporated settlements: Udell and Unionville, which together account for approximately half of the township's total population. According to the USGS, it contains five cemeteries: Clancy, Eaton, Fairview, Taylor and Unionville.