Niels Lunde Reiersen (16 February 1742 - 20 July 1795) was a Danish government official, merchant, silk manufacturer, landowner and philanthropist.

He was the owner of the Royal Danish Silk Manufactury in Copenhagen (1775-1796) as well as a founding partner of the leading trading firm De Coninck & Reiersen (1775-1790).

When it closed the following year, Reiersen was granted the title etatsråd and appointed a member of the factory commission ( Fabrikdirektionen).

[4] In early 1775, Reiersen acquired the Royal Danish Silk Manufactury (Den Kongelige Silkemanufaktur) of which his father had become a co-owner in 1760.

By testament of 30 March 1793, Reiersen left behind his wealth and possessions to Den Reiersenske Fond, a fund to "support the development and progress of industry, both through theoretical and practical measures, in Copenhagen and market towns on Zealand".