PURPOSE: To describe the incidence of anophthalmic ptosis, identify clinical factors associated with its development, and evaluate the effects of enucleation on eyelid mechanics. METHODS: In this observational cohort study, measurements and photographs were reviewed in 139 patients who underwent enucleation between 2007 and 2016. Patient demographics, pre- and postoperative eyelid measurements, and exophthalmometry were used to assess the incidence of ptosis and effects of surgery on eyelid function. RESULTS: Preoperative ptosis was common and more often present in patients with enophthalmos (p = 0.0305) or reactive blepharospasm (p < 0.0001). The incidence of new-onset ptosis and improvement of preexisting ptosis following enucleation were similar (40%). Surgical repair was performed in 7% of patients with ptosis. Contralateral levator function declined with age and was positively correlated with exophthalmometry (p < 0.0001). Anophthalmic levator function was greater with increased anterior projection of the implant (p < 0.0001) and prosthesis (p < 0.0001). Patients with larger implants had improved levator function, with (p = 0.0065) and without (p = 0.0007) the prosthesis. Superior sulcus deepening was associated with decreased levator activity, but not margin-reflex distance. CONCLUSIONS: Preoperative ptosis was common, and often related to reactive blepharospasm or enophthalmos. Levator function declined with age, and correlated to greater anterior projection of the implant and prosthesis following enucleation. The surgeon can counsel patients regarding the similar likelihood (40%) of preoperative ptosis improving and new ptosis developing after enucleation. The primary factor the surgeon can modify to improve postoperative eyelid function is to maximize implant size, which is associated with greater levator activity.