Marine turtle fibropapillomatosis is an emerging disease that affects marine turtles worldwide. This report describes the histopathological features and involvement of chelonid fibropapilloma-associated herpesvirus in marine turtle fibropapillomatosis detected in the green turtle Chelonia mydas at Príncipe Island, Gulf of Guinea. The histopathological findings confirmed the presence of fibropapillomas with both verrucous and fibromatous subtypes. Quantitative real-time PCR was used for detection of chelonid fibropapilloma-associated herpesvirus in tissue samples (n = 18) collected from afflicted (n = 10) and apparently healthy turtles (n = 2), revealing 94.4% positive samples, confirming the presence of viral sequences not only in fibropapillomatosis lesions but also in the skin of apparently healthy animals.