Clas Thunberg, Finnish speed skater (d. 1973)
Arnold Clas ("Classe") Robert Thunberg (5 April 1893 – 28 April 1973) was a Finnish speed skater who won five Olympic gold medals – three at the inaugural Winter Olympics held in Chamonix in 1924 (along with a silver and a bronze medal) and two at the 1928 Winter Olympics held in St. Moritz. He was the most successful athlete at both of these Winter Olympics, sharing the honour for 1928 Winter Olympics with Johan Grøttumsbraaten of Norway.

No other athlete ever won such a high fraction of all Olympic events at a single Games.

He was born and died in Helsinki.