- Mickey's Christmas Carol AdventureJim Razzi
- Midnight at Monster MansionSteven Otfinoski
- Midnight RogueGraeme Davis
- Million Little MistakesHeather McElhatton
- Mind BanditsStephen Mooser
- Mine of TormentsDavid Tant
- Mines of MoriaJohn D. Ruemmler, Susan Mathews
- Minotaur's MazeTimothy Knapman
- Missing Money of AlteviaTimothy Lampe
- Mission for VitriumJohn Norton
- Mission InventJohn Farndon
- Mission of the Secret Spy SquadEileen Buckholtz, Ruth Glick
- Mission to VenusWilliam Emms
- Mission to World War IIMarc Kornblatt, Susan Nanus
- Mistress of SorrowsMark Lain
- Mojo Jojo's Day OffHeather Johnson
- Mojo Jojo's Secret PaperJo Duffy
- Mona Is MissingShannon Gilligan
- Monster ExpressStephen Mooser
- Monster HouseRichie Chevat
- Monster Mix-UpBill McCay
- Monsters of the MarshDavid Tant
- Moon Dragon SummerLinda Lowery
- Moon Knight: Age of AnubisJonathan Green
- Moon QuestAnson Montgomery
- MoonrunnerStephen Hand
- Moons of MysteryChristopher Black
- Moort WoodPhillip Jackson
- Morgan Swift and the Kidnapped GoddessSara Hughes
- Morgan Swift and the Treasure of Crocodile KeySara Hughes
- Motorcross ManiaR.A. Montgomery
- Mountain Bike MayhemR.P. Proctor
- Mountain BikerEdward Packard
- Mountain of MirrorsRose Estes
- Mountain SurvivalEdward Packard
- Move the MountainsEmily Conolan
- Mr. X's Golden SchemeDonna Fletcher Crow
- MudwormIan Livingstone
- Murder at the Diogenes ClubGerald Lientz
- Murder at the Old Willow Boarding SchoolJessika Fleck
- Murder in the DarkStephen Thraves
- Murder in Tinseltown nightingaleMax Nightingale
- MurderedJames Schannep
- Murf the MonsterNora Logan
- Museum of the Living DeadHilary H. Milton
- Mutiny in SpaceR.A. Montgomery
- My Lady's ChoosingKitty Curran, Larissa Zageris
- My Left or Yours?: Hold on to Your Planet!Lloyd Cordill
- Mydnight's HeroJoe Dever
- Mystery at Loch NessRoy Wandelmaier
- Mystery at Mockingbird ManorJamie Pascal, Laurie Pascal
- Mystery at the Ball GameR. Parker McVey
- Mystery at the Bike RaceFrank Topper
- Mystery in LondonHelen Brooke
- Mystery in the MansionLauren Magaziner
- Mystery in the Murky DeepDanny McAleese, David Kristoph
- Mystery of the AncientsMorris Simon
- Mystery of the MayaR.A. Montgomery
- Mystery of the Sacred StonesLouise Munro Foley
- Mystery of the Secret RoomEllen Kushner