Alfonso II may refer to:
- Alfonso II of Asturias (791–842)
- Alfonso II of Aragon (1162–1196)
- Afonso II of Portugal (1185–1223), "the Fat"
- Alfonso, Count of Poitou (1220–1271), jure uxoris Alfonso II, Count of Toulouse
- Alfonso II of Naples (1448–1495)
- Alfonso II d'Este (1533–1597), duke of Ferrara from 1559 to 1597