The 1977 Cumnock and Doon Valley District Council Election was held on 3 May 1977, the same day as the other Scottish local government elections, and constituted the second election for the Council.
Cumnock and Doon Valley was part of the area covered by the South Ayrshire parliamentary constituency. Since 1970 the constituency had been held by the Labour MP Jim Sillars, although Sillars had left the party in 1976 in part due a belief that the Labour party's devolution proposals had been lacklustre. Having left Labour, Sillars helped found the Scottish Labour Party alongside John Robertson and Alex Neil.
The 1977 Scottish District Elections proved to be the SLP's first test. Ultimately however the party fared poorly, with their best result being seen in Cumnock and Doon Valley. Even here however the party only managed to win 2 of the councils 10 seats, although the nationalist parties - the SLP and SNP - between them polled some 42% of the vote.