Background: Dry eye disease (DED) is a multifactorial disorder characterized by tear film instability, ocular surface inflammation, and symptoms of discomfort that significantly impact patients' quality of life. Current treatments often provide only temporary relief, necessitating the exploration of novel therapeutic agents such as N-acetyl cysteine (NAC) to target underlying pathophysiological mechanisms. Objective: To evaluate the efficacy of N-acetyl cysteine in improving tear film stability and alleviating symptoms in patients with dry eye disease. Methods: This quasi-experimental study was conducted at the Department of Ophthalmology, Pak-Emirates Military Hospital, Rawalpindi, from January 2022 to May 2024. Sixty-six patients (132 eyes) aged 18-65 years, diagnosed with bilateral DED for at least three months, were enrolled. Participants were alternately assigned to the intervention group, which received NAC eye drops (0.1% w/v) administered as one drop every six hours, or the control group, which received sterile saline artificial tears (0.9%) at the same frequency. Baseline demographic and clinical data were collected. Tear Film Break-Up Time (TBUT) and Schirmer’s test scores were measured at baseline, two weeks, one month, and three months post-treatment. Additionally, symptoms of burning, itching, and foreign body sensation were assessed using a four-point scale. Data were analyzed using SPSS version 25.0, with a p-value of ≤0.05 considered statistically significant. Results: The median age of participants was 34.50 years (IQR: 16.00), with 35 (53.0%) being male. Significant improvements were observed in the NAC group compared to the control group at one and three months post-treatment. TBUT increased from a median of 7.00 seconds (IQR: 5.00) at baseline to 15.50 seconds (IQR: 8.00) at three months (p<0.001). Schirmer’s test scores improved from a median of 5.00 mm (IQR: 2.00) at baseline to 11.00 mm (IQR: 5.00) at three months (p<0.001). The NAC group also experienced a significant reduction in foreign body sensation at three months (p=0.023). Conclusion: N-acetyl cysteine is an effective treatment for improving tear film stability and reducing symptoms associated with dry eye disease. Its use offers significant benefits in both objective clinical measures and patient-reported outcomes, making it a valuable therapeutic option for managing DED.