Governments, political parties and public institutions regularly design and launch communication campaigns emphasising their successes, fostering participation in democratic acts, promoting the use of public services and seeking to boost electoral support. Accordingly, researchers in the fields of politics and public administration have long sought to enhance our understanding of how individuals perceive the performance of services offered by the private and public sectors. In this respect, conflicting findings have been reported: some studies affirm there is an anti-public sector bias, others detect a preference towards public-sector providers, and some have found no evidence of a sector bias, pro or anti. We believe it crucially important to understand the mechanisms underlying sector bias, if it exists. To address the current research gap in this area, we make use of theories and tools drawn from neuropolitics (namely, functional Magnetic Resonance Imaging, fMRI) to elucidate the neurobiological foundations of perceptions regarding the performance of public-sector service providers. The neural findings obtained reveal that brain networks associated with reward and positive values provide a neurobiological explanation for pro-public sector bias, while neural mechanisms linked to aversion, risk, ambiguity and motivated reasoning are associated with an anti-public-sector bias. The implications of these findings should be considered by policymakers; for example, to promote acceptance of public-sector service provision, people must be clearly informed about the goals achieved and other positive aspects.