| Piper maculosum L., 1753 |
| Piper magnoliifolium Jacq., 1791 |
| Piper malpasoense Tebbs, 1993 |
| Piper marginatum Jacq., 1790 |
| Piper marginecontinuum Callejas, 2020 |
| Piper martensianum C. DC., 1869 |
| Piper matudae Lundell, 1941 |
| Piper maxonii C. DC., 1920 |
| Piper mcvaughii Bornst., 1989 |
| Piper medium Jacq., 1781 |
| Piper melanocladum C. DC., 1920 |
| Piper melanostictum (Miq.) C. DC., 1869 |
| Piper melastomoides Schltdl. & Cham., 1830 |
| Piper mexicanum (Miq.) DC., 1869 |
| Piper michelianum C. DC., 1920 |
| Piper middlesexense Trel. ex Standl., 1936 |
| Piper middlesexense Trel. ex Callejas, 2020 |
| Piper miradorense C. DC., 1869 |
| Piper misantlense C. DC., 1869 |
| Piper muelleri C. DC., 1869 |