Here is a list of dinosaurs beginning with M.

1. Machairasaurus
2. Machairoceratops
3. Macrocollum
4. Macrogryphosaurus
5. Macrurosaurus
6. Magnamanus
7. Magnapaulia
8. Magnosaurus
9. Magyarosaurus
10. Mahakala
11. Mahuidacursor
12. Maiasaura
13. Maip
14. Majungasaurus
15. Malarguesaurus
16. Malawisaurus
17. Maleevus
18. Malefica
19. Mamenchisaurus
20. Mandschurosaurus
21. Manidens
22. Mansourasaurus
23. Mantellisaurus
24. Mapusaurus
25. Maraapunisaurus
26. Marmarospondylus
27. Marshosaurus
28. Martharaptor
29. Masiakasaurus
30. Massospondylus
31. Matheronodon
32. Maxakalisaurus
33. Mbiresaurus
34. Medusaceratops
35. Megalosaurus
36. Megaraptor
37. Mei
38. Melanorosaurus
39. Mendozasaurus
40. Menefeeceratops
41. Menucocelsior
42. Meraxes
43. Mercuriceratops
44. Meroktenos
45. Metriacanthosaurus
46. Microceratus
47. Microcoelus
48. Microhadrosaurus
49. Micropachycephalosaurus
50. Microraptor
51. Microvenator
52. Mierasaurus
53. Minmi
54. Minotaurasaurus
55. Miragaia
56. Mirischia
57. Mnyamawamtuka
58. Moabosaurus
59. Mochlodon
60. Mongolosaurus
61. Mongolostegus
62. Monkonosaurus
63. Monoclonius
64. Monolophosaurus
65. Mononykus
66. Montanoceratops
67. Morelladon
68. Morinosaurus
69. Moros
70. Morrosaurus
71. Mosaiceratops
72. Murusraptor
73. Mussaurus
74. Muttaburrasaurus
75. Muyelensaurus
76. Mymoorapelta