The 1878 FA Cup final was an association football match between Wanderers F.C. and Royal Engineers A.F.C. on 23 March 1878 at Kennington Oval in London. It was the seventh final of the world's oldest football competition, the Football Association Challenge Cup. Wanderers had won the Cup in the previous two seasons and on four previous occasions in total, including the first FA Cup final in 1872, in which they defeated the Engineers. The Engineers had also won the Cup, having defeated Old Etonians in the 1875 final.

Wanderers Football Club was an English association football club. It was founded as "Forest Football Club" in 1859 in Leytonstone. In 1864, it changed its name to "Wanderers", a reference to it never having a home stadium, instead playing at various locations in London and the surrounding area. Comprising mainly former pupils of the leading English public schools, Wanderers was one of the dominant teams in the early years of organised football and won the inaugural Football Association Challenge Cup in 1872. The club won the competition five times in total, including three in succession from 1876 to 1878, a feat which has been repeated only once.