Mathias Otto Leth Sommerhielm (22 August 1764 – 15 November 1827) was a Danish-Norwegian politician who served as the Norwegian prime minister in Stockholm.

[1] Mathias Otto Leth Sommerhielm was born in the seaport of Kolding in southern Denmark.

In 1801, Sommerhielm became director general of military prosecutions and in 1807 he became member of the Superior Criminal Court.

[2] After the dissolution of the union between Denmark and Norway, he attended the Meeting of Notables in Eidsvoll on 16 February 1814.

In 1822, Sommerhielm was appointed Prime Minister of Norway, following the resignation of Peder Anker due to personal illness.