Mathias Stoltenberg was a Norwegian painter. He earned his living mostly as a travelling portrait painter and furniture restorer. His paintings were later rediscovered and presented at the 1914 Jubilee Exhibition in Kristiania.

Stoltenberg was born in Tønsberg, the son of merchant and politician Carl Peter Stoltenberg and Karen Mathea Bull. He lost his sense of hearing as a child, and died in poverty in Vang in 1871.

Stoltenberg studied carpentry in Copenhagen, where he also took lessons in portrait painting with Christian August Lorentzen. Back in Norway he earned his living as a travelling portrait painter and carpenter. After his father died in 1830, the family home in Tønsberg dissolved. Stoltenberg's travels covered large parts of Norway. During the 1830s and 1840s he visited Gudbrandsdalen, Dovre, the districts around Kristaniafjorden, Northern Norway, Trondheim, Numedal, Telemark and Østerdalen. From the late 1840s he lived in Vang, Hedmark. His paintings were mostly portraits, and also landscapes.

His art was recognized after the 1914 Jubilee Exhibition at Frogner in Kristiania, and he is represented in several museums. The National Gallery of Norway has fifteen of his portraits and three landscape paintings, among them Utsikt til Vang kirke (View of Vang church) from 1863.

Stoltenberg's paintings were first described by Hans Ødegaard in 1914, in Norske malere. Mathias Stoltenberg og Lars Hertervig. Ødegaard was responsible for the exhibition of older Norwegian art at the 1914 Jubilee Exhibition. In addition to Stoltenberg, Lars Hertervig, Johannes Flintoe and Peder Balke were other more or less forgotten painters who found their way into museums and galleries after this exhibition.