Background: Eye infection is public health problem in developing countries including Ethiopia. Bacteria are major causative agents of eye infections that can lead to loss of vision. Objective: The aim of this study was to determine bacterial etiology of external eye infection, antimicrobial susceptibility profile and associated factors among patients vising eye unit of Shashamane Comprehensive Specialized Hospital. Method: A hospital-based cross-sectional study was conducted at Shashamane Comprehensive Specialized Hospital from September 1, 2018 to March 30, 2019. Specimens from external eye were collected from a total of 332 patients who visited the eye unit. Specimens were inoculated on Blood agar, Chocolate agar, MacConkey agar and Mannitol salt agar. Isolated bacteria were identified by a series of biochemical tests using standard bacteriological method. Antimicrobial susceptibility test was performed according to Clinical and Laboratory Standard Institute by disk diffusion method. Sociodemographic and clinical data were collected by using structured questionnaire. Data analysis was done using SPSS version 22.0 software package. Bivariate and multivariable logestic regressions were used to determine the association between dependent and independent variables. A P-value less than 0.05 was considered statistically significant. Result: Out of the total 332 study participants with external eye infection, 198 (60%) was culture positive. The proportion of Gram-positive and Gram-negative bacteria were 135 (68.2%) and 63 (31.8%) respectively. Among Gram-positive bacteria, S. aureus, 74 (34%) was predominant. Among Gram-negative bacteria, E. coli 17 (9%) was predominant. Most of S. aureus were resistant to penicillin. Conclusion and Recommendation: Majority of eye infection in this study was caused by bacteria; Gram positive bacteria were responsible for most cases. Expanding the study on different clinical presentation of external eye infection, the role of Chlamydia trachomatis on the eye and health education for better sanitation is mandatory.