Theravent and Optipillows are expiratory resistance devices indicated for snoring, and Bongo Rx is indicated for mild to moderate obstructive sleep apnea. The goal of this study is to compare side by side the resistance of the three devices and the pressure that they generate. The devices’ resistance was evaluated using steady air flow at 100 ml/sec or simulated breathing. We calculated the device’s resistance either at a flow rate of 100 ml/sec or as the slope of the pressure-flow curve. The pressure generated during expiration with simulated breathing was also measured. The study shows that the resistances of Theravent and Bongo Rx were identical regardless how they were calculated. The resistance of Optipillows was equivalent to resistances of Theravent and Bongo Rx when the side vent was between 50 to 75% closed. Likewise, with simulated breathing, the pressure generated during expiration was identical in Theravent and Bongo Rx, and was comparable to the expiratory pressure with Optipillows when the side vent was closed between 50 to 75%. In conclusion, the three expiratory resistance devices had comparable resistance and generate comparable expiratory pressure. Despite the fact that some devices are cleared for snoring and some for obstructive sleep apnea, any of these three devices can work for either condition. The healthcare provider can recommend whichever is most accessible to the patient. The adjustable resistance on the Optipillows provides an option for the patient to select low resistance while adapting to the device.