Unlike several countries in this guide, Italy’s language bar hasn’t moved in years. It’s stable, it’s codified, and it’s not especially forgiving about which certificate satisfies it.
Law 132/2018, converting the so-called “decreto sicurezza” (Decree-Law 113/2018) and amending Articles 5 and 9 of the 1992 citizenship law, set the bar at B1 — not less — for citizenship by residence or by marriage. It’s been in force since December 2018, and nothing found in this research suggests it’s changed since.
Accepted certifying bodies: CILS (Università per Stranieri di Siena), CELI (Università per Stranieri di Perugia), PLIDA (Società Dante Alighieri), and Roma Tre’s ele.IT. Several institutes run a specific, cheaper “citizenship B1” variant of their exam — worth knowing one real catch: that variant is usable only for the citizenship file, and failing a single section means retaking the entire exam, unlike the standard B1 exam where you can retake sections individually.
No language requirement applies to citizenship by descent (iure sanguinis) — if that’s your route, this page doesn’t apply to you at all.