- Jiménez de Enciso, Diego1
- Jiménez de Enciso, Pedro1
- John Chrysostom, Saint, -40718
- John II, King of Aragon, 1397-14791
- Juan II, King of Castile and Leon, 1405-14541
- Juana, la Loca, Queen of Castile, 1479-15552
- Juana, of Austria, Princess of Portugal, 1535-15732
- Judaism5
- Judges--Selection and appointment1
- Justa, Saint, -approximately 2871
- Justice, Administration of2
- Kekchi language1
- Kings and rulers16
- Kirchmair, Georg, 1481-15541
- Knights of Malta1
- Labyrinths1
- Ladron de Guevara family1
- Land grants3
- Land titles--Registration and transfer1
- Landowners1