Interleukin 12 (IL-12) is a key player in model systems of autoimmunity. One of the most robust genetic findings is the association of variants in the IL12B gene with psoriasis and psoriatic arthritis (PsA). This study aims to assess whether combined evidence shows the association between IL12B polymorphisms and the susceptibility to psoriasis/PsA. We conducted a systematic review to examine the association between the IL12B rs3212227 (1188A > C) and rs6887695 and psoriasis/PsA. In addition, we used studies for which combined information from all genotypes was available to compare risks in dominant and recessive model. Potential publication bias was evaluated by Egger's linear regression test. Eleven articles met the inclusion criteria and contributed data to the meta-analyses. For rs3212227, the odds ratios the minor allele for psoriasis and PsA were 0.688 (95 % CI 0.650-0.729) and 0.707 (95 % CI 0.628-0.797), respectively. Then, for rs6887695, the pooled ORs were 0.704 (95 % CI 0.670-0.739) for psoriasis and 0.677 (95 % CI 0.599-0.767) for PsA. The overall ORs for all genotypes of rs3212227 and rs6887695 were all significantly associated with psoriasis. No publication bias was presented. Taken together, our results demonstrate a significant association between IL12B gene polymorphisms and psoriasis and PsA.