Introduction: Third molar surgery can cause post-operative complications to the patient due to the presence of wound from the incision. The study aimed to compare marginal flap with para-marginal flap on postoperative complications by the measurements on pre and post-surgical plaque index (PI), bleeding on probing (BoP), maximum opening of the mouth (MOM), pain perception (PP) and post-surgical tumefaction (PT). Methods: In this double-blind randomized clinical trial, 40 patients were recruited and randomly allocated in two groups. In Group 1, third molar extraction was carried out after a marginal flap design was performed, while in group 2 a para-marginal flap was per-formed. Plaque Index, Bleeding on Probing, Maximum Mouth Opening, and Distal Probing were assessed right before and one week after surgery, while Post-operative Pain Perception and Post-operative Swelling were accounted one week following sur-gery. Results: Statistically significant difference are reported between treatment groups, as the para-marginal flap led to better outcomes for all the measured indexes. Conclusion: The para-marginal flap design may decrease the occurrence of post-operative compli-cations and discomforts after mandibular third molar surgery, compared to marginal flap design.