The purpose of this investigation was to assess the effect of platelet rich plasma (PRP) on soft tissue healing after mandibular third molar surgery. In this semi-blinded clinical trial study, 30 patients requiring surgical extraction of soft tissue impacted mandibular third molar and who indicated a willingness to return for recall visits were recruited. Patients were divided into test and control groups. In the test group, PRP was placed in the extracted socket, whereas the control group had no PRP. The mean postoperative pain score (Visual Analog Scale) and the amount of wound dehiscence were lower for the test group and it was statistically significant. Although the mean bleeding time was lower in the test group, this difference was not significant. The dry socket incidence and the mean intrinsical mouth opening were not significant between both groups. The PRP in the test group reduced pain and better soft tissue healing compared with in the control group. This study showed that topical application of PRP had a beneficial effect in enhancing socket healing after third molar surgery.