| Mammoth Bluesapalooza | Mammoth Lakes | CA | United States | August | Variety |
| Marana Bluegrass & Acoustic Music Festival | Marana | AZ | United States | March | Bluegrass and Acoustic Music |
| Mariposa Folk Festival | Granville | OH | United States | July | Folk, with strong representation of Americana, singer-songwriter, and roots music. |
| Marshall Bluegrass Festival | Marshall | MI | United States | July | Bluegrass |
| Maui Songwriters Festival | Maui | HI | United States | January | Singer-songwriter, Americana, country, folk (with a focus on Nashville songwriters) |
| Maury River Fiddlers Convention | Buena Vista | VA | United States | June | Bluegrass |
| May on the Mountain | Henagar | AL | United States | May | Bluegrass |
| Mayhaw Music Festival | Cottonwood | AL | United States | October | Bluegrass |
| Mayville Bluegrass Festival | Mayville | NY | United States | August | Bluegrass |
| MeadowGrass Music Festival | Colorado Springs | CO | United States | May | Bluegrass |
| Mempho Fest | Memphis | TN | United States | September | Blues, Indie, Rock |
| MerleFest | Wilkesboro | NC | United States | April | Bluegrass |
| Mesa Singer Songwriter Festival | Mesa | AZ | United States | July | Singer/songwriting |
| Metamora Music Festival | Metamora | IN | United States | September | Variety |
| Miche Fest | Chicago | IL | United States | July | Latin, R&B |
| Mid-Winter Bluegrass Festival | Denver | CO | United States | February | Bluegrass |
| Midsummer Bluegrass Music Festival | Manitowish Waters | WI | United States | July | Bluegrass |
| Mighty Roots Music Festival | Stovall | MS | United States | September | Americana, with strong roots in Blues, Folk, Rock, and Country, featuring singer-songwriter artists. |
| Milaca RecFest Bluegrass Festival | South Hiram | ME | United States | July | Bluegrass |
| Miles City Bluegrass Festival | Miles City | MT | United States | September | Bluegrass |
| Minnesota Bluegrass Fall Jam | Plymouth | MN | United States | November | Bluegrass |
| Minnesota Homegrown Kickoff (jamming Only) | Richmond | MN | United States | June | Bluegrass |
| Minnesota Music Festival | Minneapolis | MN | United States | May | Various genres |
| Minnesota Yacht Club Festival | Saint Paul | MN | United States | July | Alternative, Country, Rock, Pop |
| Mississippi Delta Blues Festival | Greenville | MS | United States | August | Blues, with influences of Americana, Roots, and Gospel. |
| Mississippi Songwriting Festival – Gulf Coast Edition | Ocean Springs & Gautier | MS | United States | September | Variety |
| Mississippi Songwriting Festival – The Hilton Edition | Oxford | MS | United States | March | Variety |
| Missouri River Bluegrass Festival | Center | ND | United States | June | Bluegrass |
| Mitch & Cindy’s Bluegrass Music Festival | Cortland | OH | United States | June | Bluegrass |
| MN Bluegrass & Old-Time Music Festival | Richmond | MN | United States | August | Bluegrass and Old-Time |
| Moccasin Creek Festival | Effingham | IL | United States | June | Americana, country, folk |
| Mondegreen | Dover | DE | United States | August | Jam |
| Monterey Jazz Festival | Monterey | CA | United States | September | Jazz |
| Moon Crush Cowboy Moon | Miramar Beach | FL | United States | November | Country |
| Moon River Festival | Chattanooga | TN | United States | September | Folk, with strong representation of Americana, singer-songwriter, and roots music. This festival offers a more intimate setting focused on these genres. |
| Moondance Jam | Walker | MN | United States | July | Jam, Rock |
| Moonshiner’s Ball | Mount Vernon | KY | United States | October | Bluegrass, Jam, Rock |
| Mosswood Meltdown | Oakland | CA | United States | July | Indie |
| Mount Airy Bluegrass & Old-Time Fiddlers Convention | Mount Airy | NC | United States | June | Bluegrass |
| Mount Airy Fiddlers Convention | Mount Airy | NC | United States | June | Old-Time, Bluegrass |
| Mount St. Helens Bluegrass Festival | Toledo | WA | United States | August | Bluegrass |
| Mountain City Fiddlers Convention | Mountain City | TN | United States | September | Old-Time, Bluegrass |
| Mountain Heritage Arts & Crafts Festival | Kearneysville | WV | United States | September | Bluegrass |
| Mountain Song Festival | Brevard | NC | United States | September | Bluegrass |
| Mountain Stage New Song Festival Charleston | Charleston | WV | United States | September | Primarily singer-songwriter, with strong representation of Americana, folk, and roots music, featuring a mix of established and emerging artists. |
| Mountain USA Festival | Gatlinburg | TN | United States | August | Country, Bluegrass, Folk, Americana |
| Mountain View Bluegrass Festival | Mountain View | AR | United States | November | Bluegrass |
| Mr. B’s Bluegrass Festival | Woodford | VA | United States | May | Bluegrass |
| Muscle Shoals Songwriting Festival | Muscle Shoals | AL | United States | November | Singer-Songwriter, Americana, Folk and Country |
| Music & Art in the Park | New Cumberland | WV | United States | April | Bluegrass |
| Music at The Intersection | St. Louis | MO | United States | September | Blues, Hip Hop, Jazz, R&B, Rock, Soul |
| Musikfest | Bethlehem | PA | United States | August | Country, Rock |
