Note: Determining what makes a companion is a subject for heated debate. At what point is Mickey no longer a recurring character but a companion? Are the regulars of UNIT companions? What you see here expresses no consensus but that of the co-authors’.
Susan Foreman (Carole Ann Ford) (1963–1964)
Barbara Wright (Jacqueline Hill) (1963–1965)
Ian Chesterton (William Russell) (1963–1965)
Vicki (Maureen O’Brien) (1965)
Steven Taylor (Peter Purves) (1965–1966)
Katarina (Adrienne Hill) (1965)
Sara Kingdom (Jean Marsh) (1965–1966)
Dodo Chaplet (Jackie Lane) (1966)
Ben Jackson (Michael Craze) (1966)
Polly (Anneke Wills) (1966)
Ben Jackson (Michael Craze) (1966–1967)
Polly (Anneke Wills) (1966–1967)
Jamie McCrimmon (Frazer Hines) (1966–1969)
Victoria Waterfield (Deborah Watling) (1967–1968)
Zoe Heriot (Wendy Padbury) (1968–1969)
Liz Shaw (Caroline John) (1970)
Jo Grant (Katy Manning) (1971–1973)
Sarah Jane Smith (Elisabeth Sladen) (1973–1974)
Brigadier Alistair Gordon Lethbridge-Stewart (Nicholas Courtney) (recurring character, 1970–1974)
Sergeant John Benton (John Levene) (recurring character, 1970–1974)
Captain Mike Yates (Richard Franklin) (recurring character, 1971–1974)
Sarah Jane Smith (Elisabeth Sladen) (1974–1976)
Harry Sullivan (Ian Marter) (1974–1975)
Brigadier Alistair Gordon Lethbridge-Stewart (Nicholas Courtney) (recurring character, 1974–1975)
Sergeant John Benton (John Levene) (recurring character, 1974–1975)
Leela (Louise Jameson) (1977–1978)
K9 (voice of John Leeson, David Brierley) (1977–1981)
Romana I (Mary Tamm) (1978–1979)
Romana II (Lalla Ward) (1979–1981)
Adric (Matthew Waterhouse (1980–1981)
Nyssa (Sarah Sutton) (1981)
Tegan Jovanka (Janet Fielding) (1981)
Adric (Matthew Waterhouse) (1981–1982)
Nyssa (Sarah Sutton) (1981–1983)
Tegan Jovanka (Janet Fielding) (1981–1984)
Turlough (Mark Strickson) (1983–1984)
Kamelion (voice of Gerard Flood) (1983–1984)
Peri Brown (Nicola Bryant) (1984)
Peri Brown (Nicola Bryant) (1984–1986)
Mel Bush (Bonnie Langford) (1986)
Mel Bush (Bonnie Langford) (1987)
Ace (Sophie Aldred) (1987–1989)
Grace Holloway (Daphne Ashbrook) (1996)
Rose Tyler (Billie Piper) (2005)
Mickey Smith (Noel Clarke) (recurring character, 2005)
Adam Mitchell (Bruno Langley) (2005)
Captain Jack Harkness (John Barrowman) (2005)
Rose Tyler (Billie Piper) (2006)
Mickey Smith (Noel Clarke) (2006)
Martha Jones (Freema Agyeman) (2007; recurring character, 2008–2010)
Captain Jack Harkness (John Barrowman) (recurring character, 2007–2008)
Donna Noble (Catherine Tate) (2006, 2008)
Wilfred Mott (Bernard Cribbins) (recurring character, 2008–2010)
Amy Pond (Karen Gillan) (2010–2012)
Rory Williams (Arthur Darvill) (2010–2012)
Clara Oswald (Jenna Louise Coleman) (2012–2013)
Clara Oswald (Jenna Coleman) (2014– )