| Karl Kolseth | |
| Position: | First baseman |
| Bats: | Left |
| Throws: | Right |
| Birth Date: | December 25, 1892 |
| Birth Place: | Cambridge, Massachusetts |
| Death Place: | Cumberland, Maryland |
| Debutleague: | MLB |
| Debutdate: | September 30 |
| Debutyear: | 1915 |
| Debutteam: | Baltimore Terrapins |
| Finalleague: | MLB |
| Finaldate: | October 3 |
| Finalyear: | 1915 |
| Finalteam: | Baltimore Terrapins |
| Statleague: | MLB |
| Stat1label: | Games |
| Stat1value: | 6 |
| Stat2label: | At bats |
| Stat2value: | 23 |
| Stat3label: | Hit(s) |
| Stat3value: | 6 |
| Teams: | |
Karl Dickey "Koley" Kolseth (December 25, 1892 – May 3, 1956) was a Major League Baseball first baseman who played for the Baltimore Terrapins of the Federal League in .
He began his professional career with the Lawrence Barristers of the class B New England League in 1911. After his single season in the major leagues, he returned to minor league baseball with the Chambersburg Maroons of the class D Blue Ridge League in 1916. His last minor league season was with the Easton Farmers of the Eastern Shore League in 1926. Overall, he had a .292 batting average in the minors, with his single best season batting average being .333 with Hanover and Waynesboro of the Blue Ridge League in 1920.