A prison sentence is often geared toward punishment of offenders, reduction of crime, and/or protection of the public. However, in many jurisdictions, those in prison may suffer from collateral or “invisible” consequences such as denial of their voting rights. Despite the growing global social and legal debates on prisoner disenfranchisement policy, there have been few empirical studies of this issue. We explored and compared a sample of the prisoners’ and the public's views of prisoner disenfranchisement policy in the United Kingdom. Although the public were more likely than prisoners to consider voting as important, they were less aware of prisoner disenfranchisement. A high proportion of prisoners said they would vote in prison, however, only a third had voted in the past (outside prison). Prisoners and the public held different attitudes toward prisoner disenfranchisement, and the public were more likely to view this policy as fair. Prisoners were more likely to believe that their vote could influence elections, and this best predicted their intentions to vote. These findings are further considered in relation to political party affiliation, prisoner populations, and offense types. We identify future directions for research on prisoner disenfranchisement.