A surgical site infection is an infection that develops within 30 days following a surgery in the body where the surgical incision was performed. Aim: This study aimed to assess the knowledge of medical students about SSI in western Saudi Arabia. This study aims to assess awareness of surgical site infection among medical students in clinical years in the western region of Saudi Arabia and to show the difference in knowledge between governmental universities. We performed an observational study with a cross-sectional study design. A validated structured online questionnaire was used as a study tool. The questionnaire was distributed among the medical students through online means. Our study included 441 participants, of whom 46.7% were males. Only 7.3% of participants had a good knowledge score (≥70%), whereas 58.5% had a poor knowledge score (<50%). There was a significant association between knowledge level with gender (p=0.000), university (p=0.017), current study year (p=0.000), and whether the participant had studied surgery before (p=0.006). Good knowledge was more evident among females (75%) than males (25%). Students of Umm Al Qura University had the highest prevalence of good knowledge (53.1%) among other groups. Similarly, senior students (78.1%), and students who had studied surgery before (100%) had better SSI knowledge. Awareness and level of knowledge regarding SSI among medical students are generally low. We recommend improving their knowledge of SSI by providing them with more courses and sessions.