Amenamevir (AMNV), a helicase-primase inhibitor, has recently received approval for treating human herpesvirus infections. Herein, we evaluated the efficacy of AMNV against feline herpesvirus 1 (FHV-1) in three different cell lines and compared it with that of acyclovir (ACV) and penciclovir (PCV)-nucleoside analogs currently used against FHV-1 infection. The 50% inhibitory concentrations of AMNV against FHV-1 were comparable to those of ACV in all cell lines tested, although they were 2.0 to 21.0-fold higher than those of PCV. This is the first study to have evaluated the efficacy of AMNV against animal herpesvirus, and the results suggest that AMNV could be a new option for treating FHV-1 infection with a novel mechanism of action.