Mark Larson is Vargas, the Bizarro Newman in The Bizarro Jerry (Season 8 Episode 3).

Mark Metcalf is Bob Cobb, a.k.a The Maestro in The Maestro (Season 7 - Episode 3) and in The Doll (Season 7 - Episode 16).

Mark Roberts is Seth in The Chicken Roaster (Season 8 Episode 8).

Mark Tymchyshyn is Phil Tatola in The Stand-In (Season 5 - Episode 16).

Marla Sucharetza is Nancy Klopper in The Fusilli Jerry (Season 6 - Episode 21).

Marlee Matlin is Laura, a tennis lineswoman. She appears in The Lip Reader (Season 5 Episode 6).

Martin Chow is Lew The Race (Season 6 Episode 10).

Marty Rackham is a police officer in The Trip: Part 2 (Season 4 Episode 2), and Jake Jarmel in other three episodes. The first The Sniffing Accountant (Season 5 Episode 4).

Marvin Braverman appears in The Handicap Spot (Season 4 Episode 22) and in The Opposite (Season 5 Episode 22).

Mary Jo Keenen is Deena Lazzari in three episodes. The first is The Gum (Season 7 - Episode 10).

Mary Scheer is Joan in The Kiss Hello (Season 6 Episode 17).

Maryedith Burrell is Maryedith in The Non-Fat Yogurt (Season 5 Episode 7).

Matt McCoy is Lloyd Braun in The Gum (Season 7 Episode 10) and in The Serenity Now (Season 9 Episode 3).

Maud Winchester is Pamela in The Stakeout (Season 2 Episode 1).

Maurice Godin is Misha in The Gymnast (Season 6 Episode 6).

Meagen Fay is Mrs. Burns in The Abstinence (Season 8 - Episode 9).

Megan Cole is Peggy in The Susie (Season 8 - Episode 15) and in The Apology (Season 9 - Episode 9).

Megan Mulally is Betsy, the hard of hearing George's girlfriend in The Implant (Season 4 Episode 19).

Mel Tormé is Mel Tormé in The Jimmy (Season 6 Episode 19).

Melanie Chartoff is Robin in The Fire (Season 5 Episode 20).

Melanie Good is Tall woman in The Boyfriend (Season 3 Episode 17).

Melanie Smith is Rachel Goldstein in 3 episodes. The first: The Raincoats (Season 5 Episodes 18-19).

Melinda Clarke is Alex in The Muffin Tops (Season 8 Episode 21).

Melinda McGraw is Angela in The Good Samaritan (Season 3 - Episode 20).

Melora Walters is Jane in The Hamptons (Season 5 Episode 21).

Merrin Dungey is Cashier in The Bookstore (Season 9 Episode 17).

Michael Chiklis is a Steve Pocatello in The Stranded (Season 3 Episode 10).