PURPOSE: Dacryoendoscopy (DE) is an emerging, minimally invasive, surgical technique for lacrimal outflow obstruction (LOO). This is a systematic review on the diagnostic and therapeutic use, as well as the safety of DE in the lacrimal literature. METHODS: Up to 22nd November, 2024, 259 studies were retrieved from PubMed, Cochrane Library, and Ovid MEDLINE. After removing duplicates and applying the selection criteria, 18 eligible studies were included. A risk of bias assessment was conducted. The primary outcomes included diagnostic accuracies, therapeutic outcomes, and treatment-related complications. The specifications of DE, lacrimal stents, key procedural steps, and the use of operative adjuvants were also evaluated. RESULTS: The DE provides additional endoluminal information for LOO by identifying the type (structural or secretory), the location (pre-sac or post-sac), and the pattern (focal or diffuse) of obstruction, while these parameters varied across studies. Notably, pressure-controlled, air-insufflated, high-definition DE (HDDE) provides significantly better image quality than saline-infused system. DE demonstrated variable therapeutic success, both objectively (anatomical and functional patency), and subjectively (symptomatic improvement). The use of adjuvants, such as ballon dacryoplasty, intubation, postoperative topical steroids, antibiotics, and irrigation, appeared to enhance the therapeutic outcomes. Complications were generally mild to minimum, with false passages being the commonest. DE manufactured in Japan and the "Nunchaku-type" of silicone tubes were most commonly used in the literature. CONCLUSIONS: With instrumental advances and endoscopic experience, DE showed potential and early promises to be a minimal invasive alternative for diagnosing and treating LOO of different etiologies.