Olaf Haraldsson (Old Norse: Óláfr Haraldsson) may refer to:
- Olaf Haraldsson Geirstadalf (died in 934), reputed son of King Harald Fairhair of Norway
- Olaf II of Norway (995–1030), King of Norway from 1015 to 1028
- Olaf III of Norway (c. 1050–1093), King of Norway from 1067 to 1093