Prevalence of metabolic syndrome (MetS), as a major health problem, is increasing. Very limited data exist on the effect of Cuminum cyminum L. essential oil (CuEO) on MetS components. Accordingly, this study aimed to examine the effect of CuEO supplementation on anthropometric indices, glycemic control, blood pressure, lipid profile, and insulin resistance in patients with MetS. In a randomized, triple‐blind, placebo‐controlled clinical trial, 56 patients with MetS aged 18–60 years received either 75 mg CuEO or placebo soft gel thrice daily for 8 weeks. Anthropometric indices and biochemical measurements were assessed at baseline and end of the study. At the end of study, except for diastolic blood pressure (DBP), the other assessed variables were not significantly different between two groups. In intra group analysis, placebo and CuEO groups both had nonsignificant decrements in DBP (mean difference [MD] with 95% CI: −3.31 [−7.11, 0.47] and −1.77 [−5.95, 2.40] mmHg, respectively). However, DBP was significantly lower in CuEO compared with the placebo group at the end of study (81.41 ± 5.88 vs. 84.09 ± 5.54 mmHg, MD with 95% CI: −3.98 [−7.60, −0.35] mmHg, p < .05). The results indicated that CuEO does not have any effect on MetS components, except for DBP in patients with MetS.