Subsidiarity holds that matters ought to be handled by the smallest, lowest, or least centralized authority competent to address them. A larger community — including the state — should not absorb what a family, a parish, a business, or a local body can do for itself, but should help (subsidium) these smaller communities to flourish.

Articulated by Pius XI in Quadragesimo Anno, subsidiarity protects both human freedom and genuine community against the concentration of power.