| Office: | Minister of Defence |
| Term Start: | 5 March 1926 |
| Term End: | 26 July 1926 |
| Primeminister: | Ivar Lykke |
| Predecessor: | Rolf Jacobsen |
| Successor: | Ingolf E. Christensen |
| Term Start2: | 6 March 1923 |
| Term End2: | 25 July 1924 |
| Primeminister2: | Otto B. Halvorsen Abraham Berge |
| Predecessor2: | Ivar Aavatsmark |
| Successor2: | Rolf Jacobsen |
| Term Start3: | 21 June 1920 |
| Term End3: | 22 June 1921 |
| Primeminister3: | Otto B. Halvorsen |
| Predecessor3: | Ivar Aavatsmark |
| Successor3: | Ivar Aavatsmark |
| Office4: | Member of the Norwegian Parliament |
| Term Start4: | 1 January 1925 |
| Term End4: | 31 December 1927 |
| Constituency4: | Oslo |
| Term Start5: | 1 January 1916 |
| Term End5: | 31 December 1918 |
| Constituency5: | Søndre Hedemarken |
| Birth Date: | 11 October 1867 |
| Birth Place: | Fiskum, Buskerud, United Kingdoms of Sweden and Norway |
| Death Place: | Oslo, Norway |
| Spouse: | Johanne Christine Wefring |
| Children: | Gunnar Wefring |
| Party: | Free-minded Liberal |
Karl Wilhelm Wefring (11 October 1867 – 28 September 1938) was a Norwegian physician and politician who served as Minister of Defence in the 1920s.
Wefring was first elected to the Parliament of Norway as an independent for South Hedemark for the period 1916–1818. He was the Norwegian Minister of Defence 1920–1921, 1923-1924 and 1926. He served in the parliament for Oslo, representing the Liberal Left Party in the period 19125-1927 where he held the position as president of the Odelsting.[1]
Wefring became attending physician at the national institution with responsibility for the mental ill (Statens sinnssykevesen) in 1919. He was "medisinaldirektør" ("director of health") in Norway from 1927 to 1930, and director for the National Hospital from 1930 to 1937.[1]