| Litomastiellus Mercet, 1921 |
| Litomastix Thomson, 1876 |
| Mahencyrtus Masi, 1917 |
| Mahencyrtus convexus (Howard, 1897) |
| Mahencyrtus nitidus (Howard, 1894) |
| Mahencyrtus proximus (De Santis, 1945) |
| Mariola Noyes, 1980 |
| Mariola flava Noyes, 1980 |
| Masia Mercet, 1919 |
| Melanaphycus Compere, 1947 |
| Mendozaniella Brèthes, 1913 |
| Mercetia Bakkendorf, 1965 |
| Mercetiella Dozier, 1926 |
| Mesaphycus Sugonjaev, 1960 |
| Mesencyrtus Timberlake, 1941 |
| Mesocopidosomyiia Girault, 1925 |
| Metacheiloneurus Hoffer, 1957 |
| Metaphycus Mercet, 1917 |
| Metaphycus bartletti Annecke & Mynhardt, 1972 |
| Metaphycus caridei (Brèthes, 1918) |