An experiment entitled Effect of different plant growth regulators on the growth, flowering an quality of tuberose (Polianthes tuberosa L.) cv. GKTC-4 under Prayagraj agro- climatic conditions was conducted in Horticulture Research Field, Faculty of Agriculture, Department of Horticulture, Naini Agricultural Institute, SHUATS, Prayagraj during April 2022-March 2023 with an aim to identify the most suitable plant growth regulator under the agro climatic conditions of Prayagraj. There were ten treatment replicated thrice in spacing of 0.3 m x 0.3 m randomly. Significant difference in different treatments of tuberose were recorded for all the parameters observed. From the present investigation, it is concluded that among the different treatments, the treatment T₃- GA3 @ 300 ppm was found in superior in terms of plant height (55.27 cm), plant spread (58.56 cm²), Days to bud initiation (21.33 days), days taken for first flower opening from planting (36.66 days), spike length (74.86 cm), Rachis length (44.60), No. of florets (49.73), Diameter of Florets (4.51 cm), Weight of florets(2.06g) Shelf-life (3.77 days), spike yield per plant (3.46) and flower yield for 1 ha (28.263 ton), Spike per ha (2,80,800). Among the different treatments, the highest gross return is 14, 69, 520 Rs/ha, Net return is 8, 79, 384 Rs/ha and benefit cost ratio is 2.49, obtained under the use of GA3 @300 ppm in the treatment T₃.