Field experiments were conducted in 2016 and 2017 in Tennessee to evaluate the effects of a novel Bacillus thuringiensis (Bt)-transgenic toxin, Bt Cry51Aa2.834_16, on thrips (Thysanoptera: Thripidae) and tarnished plant bug, Lygus lineolaris (Palisot De Beauvois) (Hemiptera: Miridae), in cotton. Protection from thrips injury with the Bt trait was as good or better than an insecticide-based approach. The use of the Bt trait resulted in reduced numbers of immature tarnished plant bug, particularly large nymphs, and partial protection from plant bug injury. Cotton that expressed Bt Cry51Aa2.834_16 had greater yields than the non-Bt isoline when insecticides were not used. Although Bt Cry51Aa2.834_16 reduced the need for insecticide applications, foliar-applied insecticide applications were needed to provide adequate plant protection from tarnished plant bug. The currently recommended treatment thresholds for tarnished plant bug performed similarly well for Bt Cry51Aa2.834_16 and non-Bt isolines. Insecticide applications for tarnished plant bug increased fiber quality, while Bt Cry51Aa2.834_16 had minor effects. The Bt-transgenic toxin Cry51Aa2.834_16 is expected to reduce the need for insecticide applications targeting thrips and tarnished plant bug and could be a valuable addition to an overall insect management program in cotton.