Drought tolerant (DT) corn (Zea Mays L.) hybrids are developed to provide crop protection from plant water-stress in areas prone to drought like the Intermountain West. These regions also face challenges from weeds because of the wide range of developmental and physiological mechanisms possessed by weeds that give an ecological advantage under increased temperature and water-stress. Many weeds have developed resistance to some herbicides, therefore, understanding weed interactions with DT corn is important in developing sustainable strategies for management in water-stressed environments. A two-season field experiment was conducted to evaluate the critical period of weed control (CPWC) in DT versus drought susceptible (DS) corn hybrids, exposed to optimal and reduced irrigation in Utah. Treatment combinations of the two corn hybrids, two irrigation levels, and time of weed removal were arranged in a split-split plot design with each treatment replicated four times. Exponential decay and asymptotic regression models were used to determine the CPWC based on an estimated 5% relative yield loss in corn. Up to 5% and 42% yield differences were observed between weed free and weedy plots throughout the 2021 and 2022 field seasons, respectively. The beginning and end of CPWC differed between the two corn hybrids as well as between the two irrigation levels in both seasons. CPWC was 19.5 and 28 days for DT corn under optimal irrigation in 2021 and 2022, respectively. CPWC was increased for DS corn with optimal irrigation to 52 and 35 days in 2021 and 2022, respectively. A similar result was observed with reduced irrigation for each hybrid (5 and 48.5 days for DT corn, and 35 and 50 days for DS corn in 2021 and 2022, respectively). The results suggest that use of DT corn may help reduce the need for more intensive weed management because it reduces the CPWC.