| MassBioEdEIN 22-3799632 | Education | MA | $1,302,935Small | 87.92 |
| MassINCEIN 04-3271457 | Research and Public Policy | MA | $1,950,185Small | 83.15 |
| MasterVoicesEIN 13-1606158 | Arts, Culture, Humanities | NY | $1,780,240Small | 86.08 |
| MATHCOUNTSEIN 54-1295407 | Education | VA | $2,746,171Small | 89.42 |
| Mattatuck MuseumEIN 06-0443990 | Arts, Culture, Humanities | CT | $2,420,763Small | 84.18 |
| Mattress FactoryEIN 25-1338941 | Arts, Culture, Humanities | PA | $2,030,527Small | 87.88 |
| May FestivalEIN 31-0584309 | Arts, Culture, Humanities | OH | $2,682,723Small | 89.17 |
| Maymont FoundationEIN 54-6039788 | Arts, Culture, Humanities | VA | $5,202,382Mid-sized | 88.85 |
| Mayor's Fund to Advance New York CityEIN 13-3783906 | Community Development | NY | $22,870,687Large | 87.30 |
| MAZON: A Jewish Response to HungerEIN 22-2624532 | Human and Civil Rights | CA | $6,837,288Mid-sized | 88.88 |
| MA‘O Organic FarmsEIN 99-0350803 | Education | HI | $1,580,098Small | 83.01 |
| MCC TheaterEIN 13-3391844 | Arts, Culture, Humanities | NY | $5,134,774Mid-sized | 86.29 |
| McCallum TheatreEIN 95-2834871 | Arts, Culture, Humanities | CA | $13,663,160Large | 87.50 |
| McColl Center for Art + InnovationEIN 51-0195015 | Arts, Culture, Humanities | NC | $1,899,053Small | 81.20 |
| McKee Botanical GardenEIN 65-1189895 | Environment | FL | $1,443,755Small | 81.60 |
| McLaughlin Research Institute for Biomedical SciencesEIN 81-0459235 | Health | MT | $2,615,523Small | 87.14 |
| McLean County Museum of HistoryEIN 37-1414038 | Arts, Culture, Humanities | IL | $1,226,621Small | 84.49 |
| McWane Science CenterEIN 58-1933712 | Arts, Culture, Humanities | AL | $6,970,316Mid-sized | 87.33 |
| MDS FoundationEIN 22-3283911 | Health | NJ | $3,321,416Small | 88.22 |
| Meals on Wheels of Contra CostaEIN 68-0231350 | Human Services | CA | $1,624,164Small | 84.42 |
| Meals on Wheels of GreenvilleEIN 57-0531378 | Human Services | SC | $1,871,108Small | 84.92 |
| Meals on Wheels of Johnson & Ellis CountiesEIN 75-1555153 | Human Services | TX | $2,548,467Small | 82.16 |
| Meals on Wheels of the Monterey PeninsulaEIN 94-2157521 | Human Services | CA | $1,615,923Small | 87.14 |
| Meals on Wheels of Wake CountyEIN 56-1061085 | Human Services | NC | $2,758,088Small | 86.42 |
| Meals on Wheels Plus of ManateeEIN 59-1420986 | Human Services | FL | $10,663,364Mid-sized | 86.65 |
| Meals on Wheels Programs & Services of Rockland, Inc.EIN 13-2831197 | Human Services | NY | $3,338,475Small | 84.15 |
| Meals-on-Wheels Greater San DiegoEIN 95-2660509 | Human Services | CA | $4,434,764Mid-sized | 89.77 |
| Mecklenburg County Council Boy Scouts of AmericaEIN 56-0529957 | Human Services | NC | $3,609,257Mid-sized | 87.05 |
| MEDAEIN 41-0977257 | Community Development | MN | $5,829,336Mid-sized | 88.55 |
| Medic One FoundationEIN 91-6183158 | Health | WA | $2,158,358Small | 82.32 |
| Medical Ambassadors InternationalEIN 94-2691184 | International | CA | $2,704,644Small | 86.23 |
| Medical Teams InternationalEIN 93-0878944 | International | OR | $66,914,611Large | 89.39 |
| MEDICCEIN 31-1603765 | International | CA | $2,383,775Small | 82.55 |
| MediSend InternationalEIN 75-2332074 | International | TX | $1,473,879Small | 81.40 |
| Mel Trotter MinistriesEIN 38-1410467 | Human Services | MI | $9,808,537Mid-sized | 83.29 |
| Melanoma Research FoundationEIN 76-0514428 | Health | DC | $6,018,441Mid-sized | 80.00 |
| MelwoodEIN 52-0857690 | Human Services | MD | $89,195,314Large | 80.33 |
| Memorial Hermann FoundationEIN 74-1653640 | Health | TX | $18,831,202Large | 82.91 |
| Memphis Child Advocacy CenterEIN 58-1745787 | Human Services | TN | $1,869,342Small | 88.71 |
| Memphis Jewish FederationEIN 62-0475747 | Community Development | TN | $4,505,508Mid-sized | 83.60 |
| Memphis Union MissionEIN 62-0541811 | Human Services | TN | $3,646,794Mid-sized | 81.73 |
| Memphis ZooEIN 23-7236155 | Animals | TN | $15,490,121Large | 85.38 |
| Men's Health NetworkEIN 52-1855419 | Health | DC | $805,645Small | 80.30 |
| Men's Shelter of CharlotteEIN 56-1474475 | Human Services | NC | $3,798,599Mid-sized | 85.60 |
| Mended HeartsEIN 04-6073589 | Health | TX | $2,211,111Small | 89.23 |
| Mental Health Advocacy ServicesEIN 95-3371166 | Human and Civil Rights | CA | $778,600Small | 86.58 |
| Mental Health AmericaEIN 13-1614906 | Health | VA | $3,707,175Mid-sized | 89.34 |
| Mental Health AssociationEIN 16-1395575 | Health | NY | $2,486,317Small | 89.45 |
| Mental Health ColoradoEIN 84-0446365 | Health | CO | $960,909Small | 86.80 |
| MENTOR/National Mentoring PartnershipEIN 52-1674088 | Human Services | MA | $6,787,437Mid-sized | 88.76 |
| Mentors InternationalEIN 43-1536498 | International | UT | $1,543,893Small | 87.44 |
| Mercatus CenterEIN 54-1436224 | Research and Public Policy | VA | $27,582,187Large | 88.81 |
| Mercy CenterEIN 22-2664472 | Human Services | NJ | $1,820,124Small | 85.25 |
| Mercy CorpsEIN 91-1148123 | International | OR | $311,936,065Large | 86.81 |
| Mercy Flight CentralEIN 16-1427751 | Health | NY | $8,551,804Mid-sized | 83.72 |
| Mercy For AnimalsEIN 54-2076145 | Animals | CA | $10,350,461Mid-sized | 85.19 |
| Mercy's GateEIN 84-1093341 | Human Services | CO | $1,083,068Small | 80.29 |
| Merola Opera ProgramEIN 94-6084831 | Education | CA | $3,244,658Small | 86.29 |
| Merrick Community ServicesEIN 41-0693851 | Human Services | MN | $1,534,978Small | 80.72 |
| Merrimack Valley Habitat for HumanityEIN 22-2672831 | Community Development | MA | $3,552,102Mid-sized | 89.22 |