text: Gloria LeRoy - Rose Kemper (2 episodes, season 5)
  Mary Margaret Lewis - Renee (2 episodes, season 3)
  Ruby Lewis - Chloe Carlson (2 episodes, season 8)
  Beth Littleford - Dana (2 episodes, seasons 7-8)
  Sam Lloyd - Dr. Albert Goldfine (8 episodes, seasons 1-2)
  Wayne Lopez - Clyde (3 episodes, seasons 3) and Air Marshal (1 episode, season 2)
  Aaron Lustig - Craig Lynwood (3 episodes, season 7)
  Jennifer Lyons - Cecile (2 episodes, season 2)
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  Justina Machado - Claudia Sanchez (2 episodes, season 8)
  Tanner Maguire - Zach Young, age 4 (4 episodes, seasons 1−2)
  Valerie Mahaffey - Alma Hodge (8 episodes, season 3 and 8)
  Carol Mansell - Pat Ziegler (4 episodes, season 2)
  Alec Mapa - Vern (5 episodes, seasons 2−3)
  John Mariano - Oliver Weston (2 episodes, season 2)
  Dakin Matthews - Reverend Sykes (7 episodes, seasons 1-4, 6-8)
  Helena Mattsson - Irina Korsakov (3 episodes, season 6)
  Billy Mayo - Detective Lyons (5 episodes, seasons 4-5)
  James Luca McBride - Al Kaminsky (3 episodes, season 4) and Cop at Applewhite's (1 episode, season 2)
  Eddie McClintock - Frank Helm (3 episodes, season 2)
  Melinda McGraw - Annabel Foster (3 episodes, season 1)
  Laurie Metcalf - Carolyn Bigsby (4 episodes, season 3)