Purpose <p>To translate in Italian and revalidate the Lacrimal Symptom Questionnaire (Lac-Q), a symptom-based patient-reported outcome measure (PROM) for patients undergoing dacryocystorhinostomy (DCR) for nasolacrimal duct obstruction (NDO). The original English Lac-Q was validated on 17 patients; this study expands its evaluation to a substantially larger cohort.</p> Methods <p>The Lac-Q was translated and back-translated following standardized cross-cultural adaptation guidelines. A prospective cohort of adult patients with symptomatic NDO scheduled for DCR was recruited. Participants completed the Italian Lac-Q pre- and postoperatively, along with the Munk score, the Global Rating of Change Scale (GRS), the Brief Illness Perception Questionnaire (B-IPQ), and the Hospital Anxiety and Depression Scale (HADS). The Functional Endoscopic Dye Test (FEDT) was used as an objective measure of rhinostomy patency. Internal consistency, test–retest reliability, construct validity, and responsiveness were assessed. Anchor- and distribution-based methods were applied to calculate the Minimal Clinically Important Difference (MCID).</p> Results <p>A total of 124 subjects (97 females, mean age 62.6 ± 13.4 years) were included. The Italian Lac-Q demonstrated good internal consistency (Cronbach’s α &gt; 0.7) and strong test–retest reliability (ICC = 0.94). Significant correlations were found with other PROMs and the FEDT, confirming construct validity. Responsiveness was adequate, with both symptom and social impact scores improving significantly after surgery. Patients achieving the estimated MCID aligned with those attaining surgical success.</p> Conclusions <p>The Italian Lac-Q is a reliable, valid, and responsive PROM for assessing symptoms and quality-of-life impact in patients with NDO, and represents a robust tool for evaluating outcomes in lacrimal surgery.</p>