Purpose: The aim of this systematic review was to analyze the accuracy of implant placement using computerguided surgery and to compare virtual treatment planning and outcome in relation to study type (in vitro, clinical, or cadaver). A further objective was to compare the accuracy of half-guided implant surgery with that of full-guided implant surgery. Materials and Methods: A PubMed search was performed to identify studies published between January 2005 and February 2015, searching the keywords "reliability AND dental implant planning" and "accuracy dental implant planning." Inclusion criteria were established a priori. Horizontal coronal deviation, horizontal apical deviation, angular deviation, and vertical deviation were analyzed. Results: A total of 186 articles were reviewed, and 34 fulfilled the inclusion criteria. Information about 3,033 implants was analyzed in 8 in vitro studies (543 implants), 4 cadaver studies (246 implants), and 22 clinical studies (2,244 implants). Significantly less horizontal apical deviation and angular deviation were observed in in vitro studies compared to clinical and cadaver studies, but there were no statistically significant differences in apical coronal deviation or vertical deviation between the groups. Compared to half-guided surgery, full-guided implant surgery showed significantly less horizontal coronal deviation for cadaver studies, significantly less horizontal apical deviation for clinical studies, and significantly less angular deviation for both clinical and cadaver studies. Conclusion: Implant placement accuracy was lower in clinical and cadaver studies compared with in vitro studies, especially in terms of horizontal apical deviation and angular deviation. Full-guided implant surgery achieved greater accuracy than half-guided surgery. Keywords: computer-guided accuracy, computer-guided precision, computer-guided surgery, planning in implant dentistry