Marcus Williams
- Full Name: Marcus Williams
- Species: Human
- Gender: Male
- Daughter: Valeria Williams
- 2151: Commander, aide, Vice Admiral Maxwell Forrest, Starfleet; San Francisco, United States of America, Earth (ENT: "Broken Bow")
- 2154: Aide, Vice Admiral Samuel Gardner, Starfleet; San Francisco, United States of America, Earth (ENT Novel: A Choice of Futures)
- By 2162: Captain, aide, Admiral Jonathan Archer, Starfleet; San Francisco, United States of America, Earth (ENT Novel: A Choice of Futures, Tower of Babel)