| Name | Type | Country |
|---|---|---|
| Medio Ambiente, Agua, Residuos y Energía de Cantabria | Public administration | Spain |
| Metro Bilbao | Enterprise | Spain |
| MGEP | Enterprise | |
| Microcomp | Enterprise | Spain |
| Microtiker | Enterprise | Spain |
| Ministerio de Ciencia e Innovación | Public administration | Spain |
| Ministerio de Economía y Competitividad | Public administration | Spain |
| MLC-ITS Euskadi | Enterprise | Spain |
| Mobility | Foundation | Spain |
| Mondragon Unibertsitatea | University | Spain |