The aim of this meta-analysis was to test the null hypothesis of no difference in the failure rates, marginal bone loss (MBL) and post-operative infection for implants inserted in male or female patients, against the alternative hypothesis of a difference. An electronic search without time or language restrictions was undertaken in December 2014. Eligibility criteria included clinical human studies, either randomized or not. Ninety-one publications were included, with a total of 27,203 implants inserted in men (1185 failures), and 25,154 implants inserted in women (1039 failures). The results suggest that the insertion of dental implants in male patients statistically affected the implant failure rates (RR 1.21, 95% CI 1.07-1.37, P = 0.002). Due to the limited number of studies reporting results on MBL, it is difficult to estimate the real effect of the insertion of implants in different sexes on the marginal bone level. Due to lack of satisfactory information, meta-analysis for the outcome 'post-operative infection' was not performed. The results have to be interpreted with caution due to the presence of several confounding factors in the included studies.