The 1977–78 Copa del Rey was the 76th staging of the Spanish Cup. The competition began on 14 September 1977 and concluded on 19 April 1978 with the final.

Real Betis Balompié, known as Real Betis or just Betis, is a Spanish professional football club based in Seville in the autonomous community of Andalusia. Founded in 1907, it plays in La Liga. It holds home games at the Estadio Benito Villamarín in the south of the city with a 60,720-seat capacity.