Elections for the London Borough of Merton were held on 4 May 1978 to elect members of Merton London Borough Council in London, England. This was on the same day as other local elections in England and Scotland. The whole council was up for election and the incumbent majority Conservative administration maintained its overall control of the council. This was the first election held in which no aldermen were elected onto the council. Boundary changes also meant that the number of elected seats increased by 3.