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The increasing frequency and intensity of drought caused by climate change necessitate the implementation of effective ways to increase the ability of wheat to withstand drought, with humic acid being a promising approach. Therefore, a pot experiment was conducted to determine the efficacy of exogenous humic acid on wheat under water deficit stress via a completely randomized design (CRD) with three replications. The impacts of four growing conditions, i.e., well water (65% field capacity), water deficit stress (35% field capacity), soil application of humic acid (44 mg kg−1 soil) under water deficit stress and foliar feeding of humic acid (200 ppm) under water deficit stress, were investigated on two wheat varieties (BWMRI Gom 1 and BWMRI Gom 3). The results demonstrated that water deficit stress substantially decreased the studied morphological and physiological traits, yield components and yield, in both genotypes, with the exception of the proline content of flag leaves. Compared with soil application, foliar feeding of humic acid promoted the ability of wheat to overcome stress conditions better. In the present study, humic acid as a soil application increased the grain yield by 9.13% and 13.86% and the biological yield by 9.94% and 5.19%, whereas foliar treatment increased the grain output by 24.76% and 25.19% and the biological yield by 19.23% and 6.50% in BWMRI Gom 1 and BWMRI Gom 3, respectively, under water deficit stress. Therefore, exogenous foliar humic acid treatment was more effective than soil application in alleviating the effects of drought stress on wheat.