The mysterious origins and transmission pathways of the gibbon-ape leukemia virus (GALV) and the closely related koala retrovirus (KoRV) have long been debated. Bats and rodents have been suggested as primary reservoirs for interspecies transmission, with ongoing research aiming to identify additional animal hosts for GALV-KoRV-related retroviruses. This study identifies nine rodent species as new hosts for these retroviruses. Notably, two of these hosts are African rodents, marking the first detection of this virus clade outside of the Australian and Southeast Asian regions. Among these African rodents, Mastomys natalensis, the natal multimammate mouse, harbors an endogenous GALV-KoRV-related retrovirus that is fully intact and potentially still capable of generating infectious viral particles. These findings support the hypothesis that rodents are key carriers of GALV-KoRV-related retroviruses.