P
- Pantheon in Incredible Hulk #368
- Patsy Walker in Miss America Magazine #2, November 1944 (see Hellcat)
- Penance in Generation X #1
- Phaeder in Marvel Two-in-One #71
- Phantom Rider
- I: Carter Slade in Ghost Rider #1
- II: Jamie Jacobs in Western Gunfighters #7
- III: Marshall Lincoln Slade in Western Gunfighters #7
- IV: Reno Jones in Gunhawks #1
- V: Hamilton Slade in Ghost Rider #56 (May 1981)
- Phoenix
- as Jean Grey in X-Men #101
- as Rachel Summers in Uncanny X-Men #141
- Pip the Troll in Strange Tales #179
- Plantman in Strange Tales #113
- Pluto in Thor #127
- Polaris in X-Men #49
- Porcupine in Tales to Astonish #48
- Proctor in Avengers #344
- Professor Power in Marvel Team-Up #117
- Professor Warren in The Amazing Spider-Man #31
- Professor X in X-Men #1
- Prowler in The Amazing Spider-Man #78
- Psycho Man in Fantastic Four King-Sized Special #6
- Psylocke in Captain Britain #8
- Puck in Alpha Flight #1
- Puma in The Amazing Spider-Man #256
- Punisher in The Amazing Spider-Man #129
- Puppet Master in Fantastic Four #8
Read more about this topic: List Of First Appearances In Marvel Comics Publications