Lauritz Weidemann (27 November 1775 – 1 August 1856) was a Norwegian judge, civil servant and politician.

He served as county governor for almost 35 years,[1] participated at the Norwegian Constituent Assembly in 1814, and was a member of the Parliament of Norway for several periods.

He was himself an uncle of ship constructor Hakon Adelsteen Sommerfeldt and psychiatrist Herman Wedel Major, first cousin of priest and botanist Søren Christian Sommerfeldt and grandfather of industrialist Sophus Weidemann.

He represented Kristians amt at the Norwegian Constituent Assembly at Eidsvoll in 1814.

In 1815 he published three small political proposals, one regarding the Supreme Court, one on surveying of farm land, and one on finance.