| Piper multinervium M. Martens & Galeotti, 1843 |
| Piper neesianum C. DC., 1869 |
| Piper nemorense C. DC., 1892 |
| Piper nigrum L., 1753 |
| Piper nitidum Vahl, 1804 |
| Piper novogalicianum Bornst., 1989 |
| Piper nudifolium C. DC., 1892 |
| Piper nudum C. DC., 1869 |
| Piper oaxacanum C. DC., 1869 |
| Piper obliquum Ruiz & Pav., 1798 |
| Piper oblongifructum Callejas, 2020 |
| Piper oblongum Kunth, 1816 |
| Piper obtusifolium L., 1753 |
| Piper ocosingosense Callejas, 2020 |
| Piper oradendron Trel. & Standl., 1952 |
| Piper orizabanum C. DC., 1898 |
| Piper otophorum C. DC., 1891 |
| Piper ottoniifolium C. DC., 1866 |
| Piper pachoanum C. DC., 1920 |
| Piper palenquense Callejas, 2020 |