| Piper kerberi C. DC., 1898 |
| Piper kunthii (Miq.) C. DC., 1869 |
| Piper lacunosum Kunth, 1816 |
| Piper lanceifolium Kunth, 1816 |
| Piper lanceolatum Ruiz & Pav., 1798 |
| Piper lapathifolium (Kunth) Steud., 1841 |
| Piper laurifolium Mill., 1768 |
| Piper lepturum Kunth, 1839 |
| Piper leucophyllum (Miq.) C. DC., 1869 |
| Piper liebmannii C. DC., 1872 |
| Piper lindenii (Miq.) C. DC., 1869 |
| Piper littorale C. DC., 1897 |
| Piper longepetiolatum (C. DC.) Trel., 1929 |
| Piper longispicum C. DC., 1908 |
| Piper lucaeanum Kunth, 1839 |
| Piper lundellii Trel., 1936 |
| Piper lundelliifolium Standl., 1952 |
| Piper luxii C. DC., 1894 |
| Piper macrophyllum Kunth, 1816 |
| Piper macrostachyon Vahl, 1804 |