Fallout 3 characters

Player character
There is only one player character:
 * Lone Wanderer

Joinable non player characters

 * Dogmeat
 * Jericho
 * Star Paladin Cross
 * Fawkes
 * Charon
 * Clover
 * Sergeant RL-3
 * Butch DeLoria

Agatha's House

 * Agatha

Alien Crash Site

 * Dead Recon Craft Theta Alien

Andale

 * Old Man Harris
 * Bill Wilson
 * Martha Wilson
 * Jenny Wilson
 * Jack Smith
 * Linda Smith
 * Junior Smith

AntAgonizer's Lair

 * AntAgonizer

Arefu

 * Evan King
 * Brailee Ewers
 * Ken Ewers
 * Karen Schenzy
 * Ian West

Bigtown

 * Red
 * Shorty
 * Dusty
 * Flash
 * Bittercup
 * Pappy
 * Timebomb
 * Kimba
 * Sticky

Brotherhood of Steel members throughout Fallout 3

 * Paladin Hoss
 * Initiate Pek

Canterbury Commons

 * Uncle Roe
 * Joe Porter
 * Dominic D'Ellsadro
 * Machete
 * Derek Pacion

Caravan Merchants

 * Crow
 * Doc Hoff
 * Crazy Wolfgang
 * Lucky Harith

The Citadel

 * Elder Owyn Lyons
 * Scribe Rothchild
 * Star Paladin Cross
 * Paladin Gunny
 * Paladin Bael
 * Knight Captain Durga
 * Knight Artemis
 * Scribe Peabody
 * Scribe Bowditch
 * Scribe Jameson
 * Scribe Vallincourt (Broken Steel)
 * Sawbones
 * Squire Arthur Maxson

Dukov's Place

 * Dukov
 * Cherry
 * Fantasia

Galaxy News Radio

 * Three Dog
 * Margaret
 * Knight Captain Colvin
 * Knight Dillion
 * Knight Finley

Girdershade

 * Ronald Laren
 * Sierra Petrovita

Lyons' Pride

 * Sentinel Sarah Lyons
 * Knight Sergeant Wilks
 * Knight Captain Dusk
 * Knight Captain Gallows
 * Paladin Glade
 * Paladin Kodiak
 * Knight Finley
 * Knight Dillon
 * Paladin Vargas
 * Knight Captain Colvin
 * Initiate Reddin
 * Initiate Jennings

Megaton

 * Andy Stahl
 * Colin Moriarty
 * Confessor Cromwell
 * Deputy Weld
 * Deputy Steel
 * Gob
 * Jenny Stahl
 * Leo Stahl
 * Lucas Simms
 * Billy Creel
 * Maggie
 * Megaton Settler
 * Mister Burke
 * Moira Brown
 * Mother Maya
 * Nova
 * Harden Simms
 * Stockholm
 * Wadsworth
 * Walter
 * Lucy West
 * Rory McLaren
 * Nathan Vargas
 * Manya Vargas

The Family

 * Alan
 * Brianna
 * Holly
 * Ian West
 * Justin
 * Karl
 * Robert
 * Vance

Paradise Falls

 * Eulogy Jones
 * Carolina Red
 * Cutter
 * Forty
 * Grouse
 * Jotun
 * Pronto
 * Ymir
 * Clover
 * Crimson
 * Bronson
 * Miss Jeanette
 * Bleak
 * Breadbox
 * Rory McLaren
 * Carter
 * Frank

Raven Rock

 * President John Henry Eden
 * Colonel Autumn
 * Anna Holt
 * Nathan Vargas

Republic of Dave

 * Dave
 * Bob
 * Rosie
 * Jessica
 * Rachael
 * Shawna

Rivet City

 * Abraham Washington
 * Angela Staley
 * Anna Holt
 * Armitage
 * Bannon
 * Belle Bonny
 * Brock
 * Butch DeLoria
 * C.J. Young
 * Carlos
 * Cherry
 * Christie Young
 * Cindy Cantelli
 * Diego
 * Dr. Zimmer
 * Father Clifford
 * Flak
 * Gary Staley
 * Garza
 * Harkness
 * Henry Young
 * Horace Pinkerton
 * James Hargrave
 * Janice Kaplinski
 * Lana Danvers
 * Madison Li
 * Mei Wong
 * Mister Buckingham
 * Mister Lopez
 * Paulie Cantelli
 * Preston
 * Private Jones
 * Seagrave Holmes
 * Shrapnel
 * Sister
 * Tammy Hargrave
 * Ted Strayer
 * Trinnie
 * Vera Weatherly
 * Victoria Watts

Springvale

 * Silver

Apostles of the Holy Light
The following character appear only with the Broken Steel add-on
 * Atom's Champion
 * Brother Gerard
 * Mother Curie III
 * Novice
 * Sun of Atom

Temple of the Union

 * Alejandra Torres
 * Bill Seward
 * Caleb Smith
 * Four Score
 * Hannibal Hamlin
 * Simone Cameron

Tenpenny Tower

 * Allistair Tenpenny
 * Bessie Lynn
 * Doctor Banfield
 * Mister Burke
 * Herbert Dashwood
 * Anthony Ling
 * Chief Gustavo
 * Edgar Wellington II
 * Godfrey
 * Irving Cheng
 * Lydia Montenegro
 * Margaret Primrose
 * Michael Masters
 * Millicent Wellington
 * Roy Phillips
 * Susan Lancaster
 * Shakes
 * Tenpenny Residents
 * Tiffany Cheng

Tranquility Lane (Vault 112)

 * Stanislaus Braun (as Betty)
 * Timmy Neusbaum
 * Roger Rockwell
 * Janet Rockwell
 * Martha Simpson
 * Mabel Henderson
 * Old Lady Dithers

Underworld

 * Ahzrukhal
 * Barrows
 * Carol
 * Cerberus
 * Charon
 * Crowley
 * Ethyl
 * Greta
 * Griffon (only with the Broken Steel add-on)
 * Meat
 * Moira Brown
 * Nurse Graves
 * Patchwork
 * Quinn
 * Reilly
 * Snowflake
 * Sydney
 * Tulip
 * Willow
 * Winthrop

Vault 101

 * James
 * Alphonse Almodovar
 * Amata Almodovar
 * Mister Edwin Brotch
 * Officer Herman Gomez
 * Freddie Gomez
 * Butch DeLoria
 * Stanley Armstrong
 * Andy
 * Beatrice Armstrong
 * Jonas Palmer
 * Lucy "Old Lady" Palmer
 * Allen Mack
 * Wally Mack
 * Gloria Mack
 * Tom Holden
 * Mary Holden
 * Officer O'Brian
 * Officer Richards
 * Officer Wilkins
 * Ellen DeLoria
 * Pepper Gomez
 * Paul Hannon Sr.
 * Vikki Hannon
 * Paul Hannon Jr.
 * Officer John Kendall
 * Christine Kendall
 * Floyd Lewis
 * Officer Taylor
 * Grandma Taylor
 * Officer Wolfe
 * Officer Park

Warrington Station

 * Bessie Lynn
 * Michael Masters
 * Roy Phillips

Anchorage Reclamation Simulation

 * General Chase
 * Benjamin Montgomery
 * Adrienn Adami
 * Lieutenant Morgan
 * American War Correspondent
 * Quartermaster
 * General Jingwei

Outcast Outpost

 * Defender Sibley
 * Protector McGraw
 * Defender Morrill
 * Specialist Olin

Capital Wasteland

 * Catherine
 * Tobar the Ferryman

The Ark & Dove Cathedral

 * Croatoa
 * Jackson
 * Jimson
 * Nadine
 * Woodrose

Blackhall Manor

 * Obadiah Blackhall

Calvert Mansion

 * Desmond Lockheart
 * Freki and Geri

Coastal Grotto

 * Jacob Humboldt
 * Rip Smithy
 * Plik

Disaster Relief Outpost

 * Marcella

Haley's Hardware

 * Haley

Kenny's Cave

 * Kenny

Marguerite's Shack

 * Marguerite

Pilgrim's Landing

 * Panada
 * Nadine

St. Aubin Medical Facility

 * Professor Calvert

Ruzka's Lair

 * Ruzka

Capital Wasteland

 * Prosper
 * Ramsey
 * Wernher

Haven

 * Ashur
 * Marie
 * Sandra

The Mill

 * Bone
 * Brand
 * Everett
 * Faydra
 * Grudd Bear
 * Gruber
 * Hammer
 * John Bear
 * Marco
 * Spook

Downtown

 * Adan
 * Bingo
 * Friday
 * Harris
 * Jackson
 * Kai
 * Mex
 * Midea
 * Milly
 * Nola
 * Slave Master
 * Trouble Man

Uptown

 * Duke
 * Krenshaw
 * Lulu
 * Mona
 * O-Dog
 * Vikia
 * Phantom
 * Reddup
 * Squill

Steelyard

 * Wild Bill