| Croton lundellii Standl., 1935 |
| Croton macrodontus Müll. Arg., 1865 |
| Croton magdalenae Millsp., 1889 |
| Croton magniglandulifer (V.W. Steinm.) B.W. van Ee, 2021 |
| Croton malvavisciifolius Millsp., 1916 |
| Croton manihot (Klotzsch) Baill., 1864 |
| Croton maritimus Walter, 1788 |
| Croton martinianus V.W. Steinm., 1998 |
| Croton masonii I.M. Johnst., 1931 |
| Croton matudae Lundell, 1941 |
| Croton mayanus B.L. León & Vester, 2006 |
| Croton mazapensis Lundell, 1942 |
| Croton mazapensis var. obtusifolius (Müll. Arg.) G.L. Webster, 2001 |
| Croton mcvaughii G.L. Webster, 2001 |
| Croton meissneri Müll. Arg., 1866 |
| Croton mexicanus Müll. Arg., 1865 |
| Croton mexicanus var. glabrescens Müll. Arg., 1865 |
| Croton mexicanus var. glandulosus Müll. Arg., 1865 |
| Croton mexicanus var. subintegrifolius Müll. Arg., 1865 |
| Croton michaelii V.W. Steinm., 2000 |