Blepharoptosis is present when the upper eyelid is lower than its normal anatomic position in primary gaze. This is secondary to a neuromuscular imbalance with weakening of the upper eyelid retractors in relation to the protractors. As the degree of ptosis worsens, significant functional and cosmetic concerns often arise. To adequately address these concerns, ptosis is divided into categories based on the underlying pathogenesis: aponeurotic, myogenic, neurogenic, mechanical, or traumatic. Within these categories, it is important to determine if the ptosis is congenital or acquired as diagnostic and therapeutic approaches often vary between these two distinctions. The goal of this review is to summarize the classification, evaluation, management, and potential pitfalls of both acquired and congenital ptosis.