PURPOSE: Patients' perceptions of the effectiveness of a treatment, or perceived treatment effectiveness (PTE), play an important role in medicine. This study aimed to evaluate patients' PTE in dry eye disease (DED) and investigate factors contributing to these patients' perceptions. METHODS: This cross-sectional study included 66 patients with DED. At enrollment, all patients had comprehensive ophthalmic assessment. In addition, to evaluate the patient's PTE, they were asked to use a 10-point scale ranging from "strongly disagree (score 1)" to "strongly agree (score 10)" to score their views on whether their DED treatments had been effective. Changes in clinical parameters of DED over time during their care were also evaluated retrospectively and correlated with the patients' PTE. RESULTS: The mean age of patients was 55.7 years; 79% were women. Regarding patients' PTE, 36.4% strongly (score 10) and 53.0% moderately (scores 6-9) believed that their DED treatment had been effective. However, 10.6% thought that their treatment had not been effective (scores 1-5). Less favorable PTE for the DED treatment was significantly associated with a younger age (P < 0.001), current use of antidepressant medications (P = 0.01), and a higher Ocular Surface Disease Index score (P = 0.01) at enrollment. CONCLUSIONS: A majority of patients with DED have positive perceptions regarding the effectiveness of their treatments. Less favorable perceptions are associated with more severe ocular symptoms and nonocular parameters such as younger age and current antidepressant use. In DED management, assessing patients' PTE should be considered as an important part of clinical practice.