Background: The aim of this study was to evaluate the effects of systemic parameters, laboratory findings, oral parameters, and other ocular surface parameters on ocular surface epithelial damage in patients with primary Sjögren's syndrome (pSS).Methods: A total of 82 dry eye disease (DED) patients with pSS were enrolled in this study. Ocular surface epithelial damage was measured by ocular staining score (OSS). Systemic parameters, laboratory findings including serologic markers, oral parameters, and other ocular surface parameters were collected. Other ocular surface parameter assessments such as the Schirmer’s test, fluorescein tear breakup time, meibomian gland examinations, noninvasive keratographic tear film break-up time measurements using the Keratograph® 5M were performed, and the Ocular Surface Disease Index was determined. Results: In a multivariate analysis, decreased age and increased duration of pSS were significantly related to increased logarithm-transformed OSS (β = -0.011, P = 0.043 for and β = 0.040, P = 0.008). Among the ocular surface parameters, decreased fluorescein tear breakup time and increased MGD grade were significantly associated with increased logarithm-transformed OSS (β = -0.183, P < 0.001 and β = 0.192, P = 0.049).Conclusions: Ocular surface epithelial damage in patients with pSS was associated with young age, long duration of disease, unstable tear film, and decreased meibomian gland function.