Poppo II (died 1098) was the Margrave of Carniola from 1070 and Margrave of Istria from 1096 to his death. He was the son and successor of Ulric I. His mother was Sophia, a daughter of Bela I of Hungary. He was thus of royal blood.
He married Richgard, daughter of Engelbert II of Sponheim, who governed Istria until his death on 1 April 1096. Poppo and Richgard had two daughters according to the Historia Welforum:
Because of his lack of surviving sons, he was succeeded by his younger brother Ulric II.