Harry Delbert Thiers (January 22, 1919 in Fort McKavett, Texas – August 8, 2000 in Ohio) was an American mycologist who studied and named many fungi native to North America, particularly California. Thiers taught mycology at San Francisco State University. He comprehensively revised and expanded on the North American collection of boletes and named many new species.
Species authored include:
The genus Chaetothiersia and species Cortinarius thiersii were named in his honor.