Motu Motiro Hiva or Salas y Gómez (Chile) is a small (ca. 0.15 km² of land surface, 30 m maximum elevation) and remote uninhabited subtropical volcanic island located in the Southeastern Pacific Ocean at about 415 km from the nearest island of Rapa Nui (Isla de Pascua or Easter Island, Chile). Its terrestrial flora remains poorly known with few scattered records and uncertainty on some species identification due to the sporadic and brief visits by naturalists during the past century. In this paper, we describe the vascular flora and assess the species status and relative abundance based on several field surveys conducted between 2011 and 2022. The flora comprises only four plant species including a native fern (Asplenium obtusatum G. Forst.), which is relatively rare, and three flowering plants with a prostrate and succulent habit: Sesuvium portulacastrum (L.) L., Portulaca oleracea L., and a new island record which is probably a species new to science, identified as Parietaria sp. nov. A floristic comparison made with other islands in the Southeastern Pacific Ocean shows connections with Rapa Nui, but also with Juan Fernández (Chile) located 2,500 km southeast; the Pitcairn Islands (UK), the Cook Islands, the Austral, the Gambier, the Society and the Marquesas (French Polynesia) Islands between 2,400–4,100 km west; as well as the Galápagos (Ecuador) and the Hawaiian Islands (USA) at 3,300 and 7,800 km north, respectively. Motu Motiro Hiva, one of the most isolated small uninhabited islands in the world, harbors a surprisingly poor flora compared to its relatively diverse and unique avifauna and arthropod fauna. In contrast to most other Pacific islands, it remains a relatively pristine terrestrial ecosystem, which highlights its world conservation value and the importance of its continued monitoring and protection, especially for the potential effects of sea-level rise caused by climate change.