The present review examines the evidence regarding the effect of β-glucan on variables linked to the metabolic syndrome (MetS), including appetite control, glucose control, hypertension, and gut microbiota composition. Appetite control can indirectly influence MetS by inducing a decreased energy intake, and promising results for a β-glucan intake to decrease appetite have been found using gut hormone responses and subjective appetite indicators. Beta-glucan also improves the glycemic index of meals and beneficially influences glucose metabolism in patients with type 2 diabetes or MetS, as well as in healthy subjects. Furthermore, a blood-pressure-lowering effect of β-glucan in hypertensive subjects seems fairly well substantiated. The gut microbiota composition might be an interesting target to prevent MetS, and preliminary results indicate the prebiotic potential of β-glucan. The evidence that β-glucan influences appetite control and gut microbiota in a positive way is still insufficient or difficult to interpret, and additional studies are needed in this field. Still, much evidence indicates that increased β-glucan intake could prevent MetS. Such evidence should encourage increased efforts toward the development of β-glucan-containing functional foods and promote the intake of β-glucan-rich foods, with the aim of reducing healthcare costs and disease prevalence.