| Copa del Rey | |
| Year: | 1979–80 |
| Other Titles: | 78th Copa del Rey |
| Country: |  Spain |
| Dates: | 11 September 1979 – |
| Num Teams: | 226 |
| Defending Champions: | Valencia |
| Winners: | Real Madrid CF (14th title) |
| Second: | Castilla CF |
| Matches: | 449 |
| Goals: | 1320 |
| Prev Season: | 1978–79 |
| Next Season: | 1980–81 |
The 1979–80 Copa del Rey was the 78th staging of the Spanish Cup, the annual domestic cup competition in the Spanish football. The tournament was attended by 226 teams from the main categories of Spanish football.
The tournament began on 11 September 1979 and ended on 4 June 1980 with the final, held in Santiago Bernabéu Stadium in Madrid.
The final was an unusual event as Real Madrid CF faced their reserve team Castilla CF. The final score was 6–1 with Real Madrid getting their fourteenth title. This win added to the league title gave the double (third in their history) and Castilla CF qualified directly for the next edition of the UEFA Cup Winners' Cup.
The revelation of the tournament Castilla CF, became the third team from the second division to reach the final.
The defending champions, Valencia CF, were defeated 3–2 (on aggregate score) by Sporting de Gijón in the round of 16.
| Round | Fixture | Clubs | Gain entry |
|---|---|---|---|
| First round | 110 | 226 → 116 | All Clubs participating gain entry |
| Second round | 56 | 116 → 60 | Real Sociedad, Sporting de Gijón, Atlético de Madrid (*) |
| Third round | 28 | 60 → 32 | |
| Fourth round | 14 | 32 → 18 | |
| Fifth round | 2 | 18 → 16 | |
| Round of 16 | 8 | 16 → 8 | FC Barcelona, Real Madrid CF, Valencia CF (*) |
| Quarter-finals | 4 | 8 → 4 | |
| Semi-finals | 2 | 4 → 2 | |
| Final | 1 | 2 → 1 |
| 1ª División | 18 | |
| 2ª División | 20 | |
| 2ª División B | 39 | |
| 3ª División | 148 | |
| Cto. Nacional de Aficionados | 1 | |
| Total teams | 226 |
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See main article: 1980 Copa del Rey Final.