The scientific literature has used different theoretical arguments and methodological alternatives to attempt to demonstrate whether both electoral turnout and the strength of the incumbent majority influence the cost efficiency of municipal governments, reaching inconclusive results. We provide new arguments and employ a methodology that overcomes some of the limitations of the previous studies. Our research confirms a direct association between electoral turnout and municipal cost efficiency in the Spanish region of Galicia. Moreover, the strength of the incumbent majority has a significant negative effect on cost efficiency, contradicting the frequently used explanations that are based on government inaction or the common-pool problem. KEYWORDS cost efficiency, electoral turnout, municipalities, political strength, stochastic frontier JEL CLASSIFICATION