| 1945 Norwegian Football Cup | |
| Other Titles: | Norgesmesterskapet i fotball for menn 1945 |
| Country: | Norway |
| Num Teams: | 128 (main competition) |
| Defending Champions: | Fredrikstad |
| Winners: | Lyn (5th title) |
| Second: | Fredrikstad |
| Prev Season: | 1940 |
| Next Season: | 1946 |
The 1945 Norwegian Football Cup was the 40th season of the Norwegian annual knockout football tournament. This was the first cup in five years, due to the Second World War. The tournament was open for all members of NFF, except those from Northern Norway. The final was contested by the defending champions Fredrikstad and the four-time former winners Lyn. It took two replays to decide a winner, and in the third final Lyn won 4–0 securing their fifth title and the first title in 34 years, having last won in 1911.
|-|colspan="3" style="background-color:#97DEFF"|Replay|}
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|colspan="3" style="background-color:#97DEFF"|2 September 1945|-|colspan="3" style="background-color:#97DEFF"|Replay: 9 September 1945|-|colspan="3" style="background-color:#97DEFF"|2nd replay: 13 September 1945|}
|colspan="3" style="background-color:#97DEFF"|16 September 1945|-|colspan="3" style="background-color:#97DEFF"|Replay: 19 September 1945|}
|colspan="3" style="background-color:#97DEFF"|23 September 1945|}
|colspan="3" style="background-color:#97DEFF"|30 September 1945|}
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