| ▲Nombre▼⊗ | △País▼≋ | △Provincia▼ | ▲#▼ |
|---|---|---|---|
| Martin Claret | Brasil | São Paulo | 1 |
| Midia Editorial | Chile | ¿? | 1 |
| Mary Gnaedinger (The Frank A. Munsey Company) | EE.UU. | Brooklyn, New York City | 1 |
| Metal Blade Records | EE.UU. | California | 2 |
| Mercury Record | EE.UU. | Chicago | 1 |
| Metal Mammoth, Inc. | EE.UU. | Easthampton, Massachusetts. | 1 |
| Miskatonic River Press | EE.UU. | Florida | 6 |
| Miskatonic University Podcast | EE.UU. | Internet | 3 |
| Modest Games | EE.UU. | Los Angeles, CA. | 1 |
| Mythos Books LLC | EE.UU. | Missouri | 2 |
| Millennium Publications | EE.UU. | Narragansett, Rhode Island | 7 |
| Middle Pillar Presents | EE.UU. | New York City | 2 |
| Marvel Cómics | EE.UU. | Nueva York | 7 |
| McIlwraith, Dorothy Stevens (Weird Tales) | EE.UU. | Nueva York | 4 |
| Monolith Graphics | EE.UU. | Ohio | 1 |
| Mock Man Press | EE.UU. | San Francisco | 2 |
| Mr. B Games | EE.UU. | ¿? | 1 |
Miskatonic Repository  | EE.UU. | ¿¿¿??? | 29 |
| Ediciones Minotauro | España | Barcelona | 17 |
| Editorial Molino | España | Barcelona | 8 |
| Mondadori | España | Barcelona | 4 |
| Maqui Edicions | España | Gerona | 1 |
| La Magnífica | España | Madrid | 1 |
| Ediciones Martínez Roca | España | Madrid | 14 |
| Materia Oscura | España | Madrid | 1 |