Sievert Allen Rohwer (22 December 1887 in Telluride – 12 February 1951) was an American entomologist who specialized in Hymenoptera. He was a graduate of the University of Colorado. At the time of his death, Rohwer was serving as the Coordinator Defense Activities for the Agricultural Research Administration within the U.S. Department of Agriculture. Rohwer worked for the USDA from 1909 until his death. Rohwer wrote Technical papers on miscellaneous forest insects. II. The genotypes of the sawflies or woodwasps, or the superfamily Tenthredinoidea. Technical series US Department of Agriculture, Bureau of Entomology, Washington, DC 20: 69–109 (1911) and very many papers describing new species of Hymenoptera. His collection is held by the Smithsonian Institution Washington D. C.