Psoriasis may be associated with dyslipidaemia, a known risk factor for cardiovascular disease. This systematic review aims to synthesize evidence for the association between psoriasis and dyslipidaemia. Through a systematic search using MEDLINE, Embase and the Cochrane Central Register, from 1 January 1980 to 1 January 2012, we identified 25 observational studies that met the inclusion criteria. These 25 studies included over 2·4 million participants, among whom 265 512 were patients with psoriasis. Twenty studies (80%) reported that psoriasis was significantly associated with dyslipidaemia, with odds ratios (ORs) for dyslipidaemia ranging from 1·04 to 5·55 in 238 385 patients with psoriasis, from a population of 2 340 605 participants. Specifically, four studies defining dyslipidaemia as triglyceride levels ≥ 150 mg dL−1 reported significantly increased ORs of 1·20–4·98 for hypertriglyceridaemia in psoriasis. Three studies found that patients with psoriasis presented with significantly increased ORs (1·36–1·77) for high-density lipoprotein cholesterol levels < 40 mg dL−1, and two studies found hyperlipoproteinaemia to be significantly elevated in patients with psoriasis (ORs 1·55 and 2·09). One cohort study found a significantly higher incidence of hyperlipidaemia among patients with psoriasis (hazard ratio 1·17; 95% confidence interval 1·11–1·23). Among studies that assessed the severity of psoriasis, in 2662 patients with mild psoriasis and 810 patients with severe psoriasis, higher odds of dyslipidaemia were seen in patients with severe psoriasis. Five of the 25 studies (20%) in our review did not show any significant relationship between psoriasis and dyslipidaemia. This systematic review found that psoriasis was significantly associated with greater odds and incidence of dyslipidaemia. Greater psoriasis severity appeared to be associated with higher prevalence of dyslipidaemia.