Alarba is a municipality in the province of Zaragoza, in the autonomous community of Aragon, Spain. It is a small, rural settlement in northeastern Spain, within the comarca of Comunidad de Calatayud.
The municipality is sparsely populated. According to the 2004 census carried out by Spain's national statistics institute (INE), Alarba had a population of 143 inhabitants. This figure reflects the pattern of small village populations typical of the Aragonese countryside.
As a municipality, Alarba forms part of the local administrative structure of Zaragoza province, one of the three provinces that make up Aragon alongside Huesca and Teruel.