Jón Loftsson (Modern Icelandic: [ˈjouːn ˈlɔf(t)sɔn]; Old Norse: Jón Loptsson [ˈjoːn ˈloptsˌson]; c. 1124–1197) was chieftain of Oddi at Rangárvellir in the south part of Iceland.
Jón Loftsson was a member of the Oddaverjar family clan. His parents were Loftur Sæmundsson and Þóra Magnúsdóttir.His paternal grandfather was Sæmundur Sigfússon (Sæmundr fróði). His maternal grandfather was King Magnus III of Norway. He was educated at Konghelle (Kungahälla) in Bohuslän (Båhuslen) which at that time a royal center of the Kingdom of Norway. Jón Loftsson was married to Halldóra Brandsdatter with whom he had several children.