Background: Acne vulgaris (AV) is a chronic inflammatory disorder, characterized by ‎retention of desquamated keratinocytes within the pilosebaceous unit (PSU) forming ‎a microcomedo. Interleukin (IL)-17A was seen in early AV lesions and is believed to have a role in AV development. Aim: This study aimed to assess serum IL-17 level in cases with AV to assess its role in disease pathogenesis, its correlation with disease severity and its clinical significance. Methods: This case control study was conducted on a total of 40 cases who were divided into two groups: AV group comprised 20 patients with AV, and the control group included 20 ‎age- & sex-matched healthy controls (HC). The AV severity was graded using the ‎ Global Acne Grading System (GAGS). Also, serum IL-17 concentration was estimated in both groups. Results: IL-17 level displayed significant increase in acne group compared to ‎the control group.‎ IL-17 displayed significant positive correlation with sex, smoking, ‎family history, acne scars, acne grade & GAGS score. ‎On the other hand, no correlation was noticed with disease duration and seborrheic ‎dermatitis. At cut off 57.94 (pg/ml) IL-17 displayed significant AUC that could ‎ distinguish between AV cases and HC with sensitivity 95% and ‎specificity 95%.‎ Conclusion: Serum IL-17 level can be used in diagnosis of patients with acne ‎vulgaris. Moreover, it can be used as a predictor of disease severity ‎and scarring& can be targeted as line of therapy.