Monterrubio de la Serena is a municipality in the province of Badajoz, in the Extremadura region of southwestern Spain. It lies within the comarca (district) of La Serena, from which it takes part of its name.
According to the 2014 census, the municipality had a population of 2,537 inhabitants. As a municipality, it comprises the main town together with the surrounding rural territory administered under the same local government.
Like much of the Badajoz province, Monterrubio de la Serena forms part of the wider Extremadura region, an area of western Spain that borders Portugal to the west.