The brown marmorated stink bug, Halyomorpha halys (Stal, 1855) (Hemiptera: Pentatomidae), is an invasive harmful pest species due to its economic losses. Its wide host range and continuous movement make its control difficult with insecticides. Biological control has recently gained importance due to the negative aspects of chemical control. The study evaluated the biological control tools by testing the entomopathogens against the pest by 11 bacteria strains and 1 fungal isolate. Brevibacillus, Bacillus, Pantoea, Vibrio, Pseudomonas, and Beauveria were tested against the nymphs of H. halys under controlled conditions. All applied entomopathogens had potentials for controlling H. halys. Mortality rates of 75 and 100% were obtained by the bacteria strains and 76.19% by the fungus, B. bassiana. Successfully reaching a 100% control rate, the bacterial isolates of the Bacillus cereus GC subgroup B and Pantoea agglomerans GC subgroup were recorded to have a greater potential than the others.