| Men's Shelter of CharlotteEIN 56-1474475 | Human Services | NC | $3,798,599Mid-sized | 85.60 |
| Mental Health AmericaEIN 13-1614906 | Health | VA | $3,707,175Mid-sized | 89.34 |
| Mental Health Association in TulsaEIN 73-0657931 | Health | OK | $8,922,886Mid-sized | 93.59 |
| MENTOR/National Mentoring PartnershipEIN 52-1674088 | Human Services | MA | $6,787,437Mid-sized | 88.76 |
| MEOREIN 51-0430002 | Religion | NY | $6,140,357Mid-sized | 78.94 |
| 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 Health ClinicEIN 52-2230932 | Health | MD | $4,048,072Mid-sized | 90.94 |
| Mercy Medical AngelsEIN 52-1374161 | Health | VA | $5,018,101Mid-sized | 91.62 |
| Merit School of MusicEIN 36-3028768 | Education | IL | $6,758,072Mid-sized | 90.31 |
| Merrimack Valley Habitat for HumanityEIN 22-2672831 | Community Development | MA | $3,552,102Mid-sized | 89.22 |
| Mesa United WayEIN 86-0198599 | Community Development | AZ | $4,028,932Mid-sized | 95.47 |
| Mesorah Heritage FoundationEIN 11-2981112 | Religion | NY | $8,542,211Mid-sized | 84.50 |
| Messenger InternationalEIN 59-3123555 | Religion | CO | $6,491,166Mid-sized | 94.13 |
| Metrocrest Social ServicesEIN 75-1548334 | Human Services | TX | $5,543,047Mid-sized | 92.38 |
| Metropolitan Planning CouncilEIN 36-2382849 | Community Development | IL | $4,318,517Mid-sized | 90.95 |
| Mexican American Legal Defense and Educational FundEIN 74-1563270 | Human and Civil Rights | CA | $6,747,829Mid-sized | 87.37 |
| Miami Lighthouse for the Blind and Visually ImpairedEIN 59-0637847 | Human Services | FL | $8,315,513Mid-sized | 98.14 |
| Michigan Theater FoundationEIN 38-2269013 | Arts, Culture, Humanities | MI | $4,853,236Mid-sized | 90.39 |
| Middle East ForumEIN 23-7749796 | Research and Public Policy | PA | $3,682,718Mid-sized | 88.61 |
| Middle East InstituteEIN 53-0204608 | International | DC | $5,814,897Mid-sized | 97.12 |
| Middle Georgia Community Food BankEIN 58-2484086 | Human Services | GA | $10,581,893Mid-sized | 89.45 |
| Middleton Outreach MinistryEIN 39-1484945 | Human Services | WI | $3,838,549Mid-sized | 96.66 |
| Midwest Athletes Against Childhood CancerEIN 39-1270290 | Health | WI | $4,138,694Mid-sized | 95.07 |
| MIFA (Metropolitan Inter-Faith Association)EIN 62-0803601 | Human Services | TN | $9,032,602Mid-sized | 86.92 |
| Migration Policy InstituteEIN 52-2279789 | International | DC | $6,001,797Mid-sized | 91.90 |
| Millennium Relief & Development ServicesEIN 76-0574590 | International | TX | $4,170,539Mid-sized | 73.52 |
| Millionair Club CharityEIN 91-0607513 | Human Services | WA | $6,538,256Mid-sized | 92.24 |
| Milwaukee BalletEIN 39-1134735 | Arts, Culture, Humanities | WI | $6,450,332Mid-sized | 89.90 |
| Milwaukee Repertory TheaterEIN 39-0946025 | Arts, Culture, Humanities | WI | $11,651,807Mid-sized | 94.90 |
| Mind & Life InstituteEIN 77-0284767 | Research and Public Policy | VA | $3,552,029Mid-sized | 89.22 |
| Mingei International MuseumEIN 23-7433357 | Arts, Culture, Humanities | CA | $3,695,785Mid-sized | 79.45 |
| Ministry of CaringEIN 51-0209843 | Human Services | DE | $10,407,336Mid-sized | 94.95 |
| Minnesota Children's MuseumEIN 41-1354181 | Arts, Culture, Humanities | MN | $9,321,847Mid-sized | 88.69 |
| Minnesota OperaEIN 41-0946789 | Arts, Culture, Humanities | MN | $11,190,288Mid-sized | 85.27 |
| Minnesota Zoo FoundationEIN 51-0147653 | Animals | MN | $3,820,920Mid-sized | 85.60 |
| Minnetrista Gathering PlaceEIN 35-1628916 | Arts, Culture, Humanities | IN | $4,487,847Mid-sized | 80.09 |
| Miracle FlightsEIN 88-0209952 | Health | NV | $3,726,507Mid-sized | 76.73 |
| Miriam's KitchenEIN 52-1331552 | Human Services | DC | $4,421,295Mid-sized | 92.92 |
| Mises InstituteEIN 52-1263436 | Research and Public Policy | AL | $4,165,289Mid-sized | 94.70 |
| Mission Arlington/Mission MetroplexEIN 75-2354962 | Religion | TX | $3,860,708Mid-sized | 96.15 |
| Mission EurasiaEIN 35-1835273 | Religion | IL | $4,262,417Mid-sized | 86.84 |
| Mission of MercyEIN 86-0704883 | Health | PA | $7,151,522Mid-sized | 93.89 |
| Missionary Flights InternationalEIN 23-7199063 | Religion | FL | $4,326,147Mid-sized | 74.94 |
| Mississippi Center for JusticeEIN 13-4203234 | Human and Civil Rights | MS | $3,606,434Mid-sized | 86.39 |
| Mississippi Children's MuseumEIN 64-0850010 | Arts, Culture, Humanities | MS | $3,541,158Mid-sized | 97.17 |
| Missoula Food BankEIN 81-0414143 | Human Services | MT | $4,608,782Mid-sized | 93.32 |
| MN Community MeasurementEIN 35-2246162 | Research and Public Policy | MN | $3,570,442Mid-sized | 83.18 |
| Mobile Loaves & FishesEIN 74-2956081 | Human Services | TX | $6,045,166Mid-sized | 98.23 |
| Modesto Gospel MissionEIN 94-6102833 | Human Services | CA | $6,196,894Mid-sized | 81.69 |
| Mohonk PreserveEIN 14-1609484 | Environment | NY | $4,259,553Mid-sized | 81.21 |
| MoMA PS1EIN 23-7379091 | Arts, Culture, Humanities | NY | $9,938,950Mid-sized | 82.27 |
| Monell Chemical Senses CenterEIN 23-2020897 | Health | PA | $13,342,596Mid-sized | 86.45 |
| Monmouth County SPCAEIN 21-0679893 | Animals | NJ | $5,004,059Mid-sized | 83.71 |
| Montalvo Arts CenterEIN 94-1249283 | Arts, Culture, Humanities | CA | $5,707,512Mid-sized | 92.12 |
| Montclair Art MuseumEIN 22-1487582 | Arts, Culture, Humanities | NJ | $4,778,160Mid-sized | 87.47 |
| Montgomery County Women's CenterEIN 76-0061208 | Human Services | TX | $5,849,609Mid-sized | 89.33 |
| Montpelier FoundationEIN 31-1620682 | Arts, Culture, Humanities | VA | $11,496,518Mid-sized | 86.75 |
| More Than WordsEIN 04-2784985 | Human Services | MA | $4,031,601Mid-sized | 90.58 |
| MorningStar Mission MinistriesEIN 36-2422510 | Human Services | IL | $6,723,363Mid-sized | 89.50 |