<p>Low grain setting rate seriously affected the yield of Tartary buckwheat. Plant hormones are shown to play an important role in plant growth and development. This study aimed to clarify the effects of plant hormones on grain setting and economic benefits of Tartary buckwheat.&#xa0;A 2-year field experiment was conducted on Tartary buckwheat variety Jinqiao 2 using five treatments, including 0 (control), abscisic acid (ABA, 10 µmol L^− 1), fluridone (ABA synthesis inhibitor, 10 µmol L^− 1), strigolactone (SL, rac-GR24, 10 µmol L^− 1), and SL synthesis inhibitor (Tis-108, 10 µmol L^− 1), applied at the early budding stage.&#xa0;The ABA and Tis-108 treatments significantly increased the 100-grain weight, plant height, and number of main stem nodes and branches; significantly increased photosynthetic parameters and antioxidant enzymes activities. In addition, both treatments significantly increased the number of mature grains and flowers and grain setting rate but significantly reduced the grain abortion rate. Compared with control, the Tis-108 treatment increased the grain number per plant, grain weight per plant, 1000-grain weight, and yield by 14.55%, 17.90%, 13.32%, and 24.04%, respectively. The Tis-108 and ABA treatments increased the production value and net output value of Tartary buckwheat, whereas only the ABA treatment significantly increased economic output/input ratio and output/cost ratio, which were 12.80%, and 15.19% higher than those of the control, respectively.&#xa0;ABA treatment (10 µmol L^− 1) is a feasible agronomic method for improving the yield of Tartary buckwheat.</p>