Background: Brow-lift-induced eyelid closure impairment is commonly discussed in patients with facial paralysis but has not been well quantified. Objective: To measure the limitation of eyelid closure in patients with facial paralysis using simulated brow-lift with tape. Design, Setting, and Participants: For 50 facial paralysis patients with brow ptosis who visited our institution from October 2017 to December 2020, brow-lift was simulated by elevating the paralyzed-side brow using surgical tape, and closed palpebral fissure heights in spontaneous blinking were measured using high-speed videography. The effect of several factors on the change in closed palpebral fissure height was evaluated by multiple linear regression analysis. Results: Greater patient age (p = 0.021), single eyelids (p = 0.003), higher value of closed palpebral fissure height before simulation (p = 0.004), and higher value of brow elevation (p = 0.013) were significant for the increase of closed palpebral fissure height. Conclusions: Brow elevation to the degree that achieves symmetrical brow height could be detrimental to eyelid closure in patients with facial paralysis, especially who are elderly, have single eyelids, or present with preoperative decreased lid-closure function. UMIN Clinical Trials (UMIN Registry No. 000042974).