Orthognathic surgery is a well-known surgical procedure for correction of facial deformities. The surgical procedure is performed by the use of conventional plates and by patient-specific osteosynthesis plates (PSOPs). The aim of this study is to investigate any differences in complications, financial expenses, professional and patient-reported outcome measures (PROM) in orthognathic surgery performed by conventional plates and by PSOPs. A MEDLINE (PubMed), Embase, and Cochrane Library search was conducted. Human studies published in English through August 27, 2020 were included. Grey literature, unpublished literature as well as other databases like Scopus, Google Scholar, or Research Gate were also included in the search strategy of the present systematic review. Randomized and controlled clinical trials were included. Risk of bias was assessed by Cochrane risk of bias tool and Newcastle-Ottawa Scale. Five studies with unclear risk of bias and moderate quality were included. Meta-analysis was not applicable due to considerable heterogeneity. There was no significant difference in intra- and postoperative complications or professional and PROM with the two treatment modalities, although higher tendencies to reoperations were observed with conventional plates. Financial expenses were significantly higher with PSOP, but treatment planning and intraoperative time were shortened by approximately one third compared with mock surgery and conventional plates. No significant differences were observed in complications, professional and PROM. Higher financial expenses were recorded in orthognathic surgery performed with PSOP. Treatment planning and intraoperative time were shortened with the use of conventional plates. Although further randomized trials are needed before definite conclusions can be provided about beneficial use of PSOPs in orthognathic surgery from a professional and patient perspective.