Abstract: A study was conducted to investigate the effect of plant growth regulators on dry matter production and growth attributes of soybean. Plants of soybean Cv. PB-1 were sprayed three times (T1 = spray at 15 DAS, T2 = spray at 30 DAS and T3 = spray at 45 DAS) with two concentrations (100 and 200 ppm) of Gibberellic Acid (GA3) and Maleic Hydrazide (MH). The results of the experiment revealed that significant variations exist with the time of application in respect of dry matter production in root, stem, leaf and total dry matter per plant and growth attributes like Leaf Area Index (LAI), Crop Growth Rate (CGR), Relative Growth Rate (RGR) and Net Assimilation Rate (NAR). CGR and NAR were increased up to 80 DAS and thereafter decreased due to maturity with respect of time of spray and concentration of growth regulators. However, LAI and RGR were maximized at 100 and 60 DAS, respectively. T2 produced the highest root, stem, leaf and total dry matter, LAI, CGR, RGR and NAR followed by T3 and T1 produced the least of them. All growth regulators had positive effect in dry matter production and growth of soybean over non-sprayed control plants. GA3 was more effective than MH. However, 100 ppm GA3 had the most regulatory effect to enhance root, stem, leaf and total dry matter, LAI, CGR, RGR and NAR followed by 200 ppm GA3. 200 ppm MH was least effective among the treatments. Interaction between T2C3 (spray at 30 DAS x 100 ppm GA3) brought about the best improvement in dry matter production and growth of soybean.