| Mother Caroline Academy & Education CenterEIN 04-3163180 | Education | MA | $2,529,195Small | 85.11 |
| mothers2mothersEIN 30-0545760 | International | CA | $4,284,671Mid-sized | 80.54 |
| Motion Picture and Television FundEIN 95-1652916 | Human Services | CA | $58,204,376Large | 84.86 |
| Motor Racing OutreachEIN 58-1859610 | Religion | NC | $2,104,717Small | 78.75 |
| Moultrie YMCAEIN 58-0593424 | Human Services | GA | $3,989,387Mid-sized | 85.15 |
| Mount Carmel MinistriesEIN 41-1577937 | Religion | MN | $1,230,287Small | 85.10 |
| Mount Desert Island Biological LaboratoryEIN 01-0202467 | Research and Public Policy | ME | $11,741,518Mid-sized | 92.61 |
| Mount Sinai Medical Center FoundationEIN 59-1711400 | Health | FL | $5,220,734Mid-sized | 71.34 |
| Mount Washington ObservatoryEIN 02-0225135 | Research and Public Policy | NH | $2,066,258Small | 81.07 |
| Mountain Association for Community Economic DevelopmentEIN 31-0900246 | Community Development | KY | $5,071,264Mid-sized | 96.63 |
| Mountain HumaneEIN 82-0351171 | Animals | ID | $2,454,867Small | 92.81 |
| Mountain States Children's HomeEIN 84-0516736 | Human Services | CO | $2,131,358Small | 80.89 |
| Mountain States Legal FoundationEIN 84-0736725 | Human and Civil Rights | CO | $2,497,281Small | 78.73 |
| MountainfilmEIN 84-1271056 | Arts, Culture, Humanities | CO | $1,909,898Small | 74.18 |
| Mountains to Sound Greenway TrustEIN 91-1531234 | Environment | WA | $3,230,631Small | 96.46 |
| Mourning Family FoundationEIN 65-1075983 | Human Services | FL | $2,110,264Small | 81.40 |
| MouseEIN 13-3973196 | Education | NY | $2,010,423Small | 94.27 |
| Move America ForwardEIN 84-1627277 | Human Services | CA | $2,977,679Small | 87.25 |
| Moving Picture InstituteEIN 20-3237801 | Arts, Culture, Humanities | NY | $3,489,969Small | 97.87 |
| Moving TraditionsEIN 34-2015014 | Religion | PA | $2,845,374Small | 89.13 |
| Mozilla FoundationEIN 20-0097189 | Education | CA | $24,206,401Large | 96.07 |
| MPN Research FoundationEIN 36-4330967 | Health | IL | $1,929,928Small | 89.03 |
| Ms. Foundation for WomenEIN 23-7252609 | Human and Civil Rights | NY | $7,138,935Mid-sized | 79.00 |
| MSPCA-AngellEIN 04-2103597 | Animals | MA | $64,880,058Large | 92.20 |
| Muhammad Ali CenterEIN 61-1323046 | Arts, Culture, Humanities | KY | $5,711,406Mid-sized | 89.16 |
| Mujeres Latinas en AcciónEIN 36-2877520 | Human Services | IL | $3,109,740Small | 86.87 |
| Mujeres Unidas Y ActivasEIN 20-2986926 | Human and Civil Rights | CA | $2,249,884Small | 86.54 |
| Multidisciplinary Association for Psychedelic StudiesEIN 59-2751953 | Health | CA | $3,572,643Mid-sized | 84.13 |
| Multiple Sclerosis FoundationEIN 59-2792934 | Health | FL | $7,701,261Mid-sized | 75.54 |
| Multiplying GoodEIN 52-0959336 | Education | NY | $2,882,955Small | 83.75 |
| Muncie Mission MinistriesEIN 35-0869061 | Human Services | IN | $1,655,329Small | 81.06 |
| Museum at Eldridge StreetEIN 13-3379555 | Arts, Culture, Humanities | NY | $1,386,823Small | 86.45 |
| Museum of African American HistoryEIN 04-2429556 | Arts, Culture, Humanities | MA | $2,130,789Small | 73.24 |
| Museum of American FinanceEIN 13-3540880 | Arts, Culture, Humanities | NY | $4,447,277Mid-sized | 78.86 |
| Museum of Arts & DesignEIN 13-3585408 | Arts, Culture, Humanities | NY | $12,077,991Mid-sized | 83.32 |
| Museum of Arts & SciencesEIN 59-1022050 | Arts, Culture, Humanities | FL | $3,921,662Mid-sized | 89.39 |
| Museum of Arts and SciencesEIN 58-0806933 | Arts, Culture, Humanities | GA | $1,321,620Small | 87.56 |
| Museum of Aviation at Robins AFB Georgia FoundationEIN 58-1451656 | Arts, Culture, Humanities | GA | $2,635,290Small | 82.04 |
| Museum of Contemporary Art DenverEIN 84-1366092 | Arts, Culture, Humanities | CO | $4,318,686Mid-sized | 83.66 |
| Museum of Contemporary Art San DiegoEIN 95-1855640 | Arts, Culture, Humanities | CA | $8,424,727Mid-sized | 82.72 |
| Museum of Contemporary Art, ChicagoEIN 36-6154098 | Arts, Culture, Humanities | IL | $21,058,376Large | 87.71 |
| Museum of Craft and DesignEIN 55-0830529 | Arts, Culture, Humanities | CA | $1,789,334Small | 81.27 |
| Museum of Danish AmericaEIN 42-1204613 | Arts, Culture, Humanities | IA | $1,401,149Small | 86.43 |
| Museum of DiscoveryEIN 71-0391707 | Arts, Culture, Humanities | AR | $3,204,869Small | 82.95 |
| Museum of Discovery and ScienceEIN 59-1709542 | Arts, Culture, Humanities | FL | $9,225,857Mid-sized | 96.64 |
| Museum of Fine Arts, BostonEIN 04-2103607 | Arts, Culture, Humanities | MA | $116,703,506Large | 85.68 |
| Museum of FlightEIN 91-0785826 | Arts, Culture, Humanities | WA | $23,340,173Large | 92.15 |
| Museum of GlassEIN 91-1669422 | Arts, Culture, Humanities | WA | $4,684,363Mid-sized | 86.45 |
| Museum of Latin American ArtEIN 33-0786070 | Arts, Culture, Humanities | CA | $3,997,352Mid-sized | 81.92 |
| Museum of New Mexico FoundationEIN 85-0202503 | Arts, Culture, Humanities | NM | $5,184,980Mid-sized | 93.44 |
| Museum of Photographic ArtsEIN 95-2889390 | Arts, Culture, Humanities | CA | $2,843,158Small | 91.45 |
| Museum of ScienceEIN 04-2103916 | Arts, Culture, Humanities | MA | $62,392,418Large | 87.76 |
| Museum of Science and Industry, ChicagoEIN 36-2167797 | Arts, Culture, Humanities | IL | $64,390,473Large | 85.34 |
| Museum of South Texas HistoryEIN 23-7080936 | Arts, Culture, Humanities | TX | $1,716,549Small | 87.91 |
| Museum of the City of New YorkEIN 13-1624098 | Arts, Culture, Humanities | NY | $21,990,267Large | 93.58 |
| Museum of the Moving ImageEIN 11-2730714 | Arts, Culture, Humanities | NY | $6,904,332Mid-sized | 83.07 |
| Museum of the Shenandoah ValleyEIN 54-1857973 | Arts, Culture, Humanities | VA | $5,590,733Mid-sized | 96.74 |
| Museum of Ventura CountyEIN 95-1942930 | Arts, Culture, Humanities | CA | $1,611,024Small | 78.87 |
| Museum of Wisconsin ArtEIN 39-1017647 | Arts, Culture, Humanities | WI | $2,108,940Small | 85.51 |
| Music Academy of the WestEIN 95-1525814 | Education | CA | $10,929,662Mid-sized | 92.89 |