Bernard John Gehrmann (February 13, 1880 – July 12, 1958) was a German American immigrant, farmer, and Progressive Republican politician.

He was employed in a packing plant in Chicago, Illinois, and later learned the printing trade on a German-language daily newspaper.

He moved to Wisconsin and settled on a farm near Neillsville, in Clark County in 1896 and engaged in agricultural pursuits.

Gehrmann conducted farmers' institutes throughout the State for the University of Wisconsin College of Agriculture from 1920 to 1933.

He engaged in work for the United States Department of Agriculture from January 1943 to April 1945.