Malignant catarrhal fever (MCF) is caused by a group of gammaherpesviruses that primarily affect domestic and wild ruminants. Using competitive-inhibition enzyme-linked immunosorbent assay, we screened 3,339 apparently healthy, semidomesticated reindeer (Rangifer tarandus tarandus) from Finnmark County, Norway, sampled during slaughter. The overall antibody prevalence was 3.5% and varied among reindeer herding districts in Finnmark (0–6.7%), the largest reindeer herding region in Norway. The risk of exposure to gammaherpesvirus (i.e., seroconversion) was significantly higher for adult reindeer than it was for calves ≤1 yr, for reindeer in east Finnmark (3.8%) compared with west Finnmark (3.3%), and with increasing population density. No evidence of disease associated with this virus was detected in reindeer sampled for this study, but because samples were collected at slaughterhouses, one cannot discard the possibility of these events happening in the field. The low antibody prevalence could indicate occasional infection of reindeer with another ruminant gammaherpesvirus or the presence of a yet-unknown, specific, low-pathogenic reindeer gammaherpesvirus. Further studies should aim at characterizing the virus circulating in reindeer and address the potential clinical impact of this virus.