Per Bengt Magnus Ingemar Rösiö (14 May 1927 – 19 May 2019) was a Swedish diplomat and author. He served as Ambassador to 17 countries and authored 20 books, mainly on diplomacy. He is more widely known however for having conducted the Swedish government's inquiry into the death of the UN Secretary General Dag Hammarskjöld where he maintained that there was no foul play.