Piper in the Philippine Islands is reviewed. Fifteen climbing species are recognized (many fewer than in previous treatments) and distinguished in a key. Most are widely distributed through Malesia, with ranges that end eastwards in the Solomon Islands or Australia. Piper myrmecophilum, the only taxon accepted as endemic to the Philippines, is ant-associated. Piper celtidiforme, once thought endemic, also occurs in New Guinea and the Solomons. The five shrubby Piper species in the Philippines are briefly described.