William Simmian "Willis" Kienholz (October 10, 1875 – September 20, 1958) was an American football player and coach.
He served one-year stints as the head coach at six different colleges: Lombard College in Galesburg, Illinois (1903), North Carolina College of Agriculture and Mechanic Arts—now North Carolina State University (1904), the University of Colorado at Boulder (1905), University of North Carolina at Chapel Hill (1906), Auburn University (1907), and Washington State University (1909).
Kienholz played football at the University of Minnesota in 1898 and 1899.