Purpose: To evaluate the effect of obturator bulb thickness on the masticatory performance and weight of obturator prostheses in edentulous hemimaxillectomy patients. Materials and Methods: A randomized, single-blind, three-period crossover trial was conducted with 17 edentulous patients. Each patient was provided with three definitive 3D-printed obturator prostheses. Obturators were divided into three groups: group 1 (G1; 1-mm bulb); group 2 (G2; 2-mm bulb); and group 3 (G3; 3-mm bulb). After fabrication, the weight of each obturator was measured with a digital analytical balance. The patients used each obturator for a period of 2 weeks without a passive period (ie, they did not stop using the obturator). The masticatory function of each obturator was evaluated with an adapted Sato questionnaire and the sieve test. Data were analyzed using one-way ANOVA and Pearson correlation analysis (α = .05). Results: According to the results of the Sato questionnaire and sieve test, G1 demonstrated the highest masticatory function scores (70.88 ± 9.39; 1.06 ± 0.06), while G3 exhibited the lowest scores (48.23 ± 7.69; 0.92 ± 0.05; P < .001). The weight of the obturators was significantly different between groups (G1 = 31.58 ± 1.09 g; G2 = 33.99 ± 1.21 g; G3 = 36.57 ± 1.13 g; P < .001). The correlation between masticatory function and the weight of the obturator was significant (P < .05). Conclusions: This study revealed that 1-mm obturator bulb thickness was an effective fabrication method for improving masticatory function and reducing the weight of obturator prostheses in edentulous hemimaxillectomy patients.