A comprehensive evaluation of the risk of serious infections in biologic therapies for psoriasis is lacking. We performed a systematic review and meta-analysis (RevMan 5.3) of randomised controlled trials (RCT) and prospective cohort studies reporting serious infection in people taking any licensed biologic therapy for psoriasis compared with those taking placebo; non-biologic therapy; or other biologic therapies. The quality of the studies was assessed using GRADE. No significant heterogeneity was detected in data from 32 RCTs (13359 participants) and one cohort study (4993 participants). In adults, low to very low quality RCT data showed no significant difference between any biologic therapy and placebo at weeks 12-16 (overall pooled Peto odds ratio[OR] 0.71, 95% confidence interval[CI]: 0.36,1.41) and weeks 20-30 (OR 2.27, 95%CI 0.45,11.49). No significant differences were found in any of the other comparisons in underpowered RCT data. Prospective cohort study data of low quality suggests only adalimumab (adjusted hazard ratio 2.52, 95%CI 1.47,4.32) was associated with a significantly higher risk of serious infection compared with retinoid and/or phototherapy in adults. No association between biologic therapies and serious infections in patient with psoriasis who were eligible for RCTs was detected. Further observational studies are needed to inform the uncertainty around this risk in the real-world. (PROSPERO number:2015:CRD42015017538).