Glenn Franklin Howerton III (born April 13, 1976) is an American actor of television and film. He is best-known for his role as Dennis Reynolds on FX's It's Always Sunny in Philadelphia (on which he is also a writer and executive producer). He also played Corey Howard on the short-lived 2002 sitcom That '80s Show. Description above from the Wikipedia article Glenn Franklin Howerton, licensed under CC-BY-SA, full list of contributors on Wikipedia.

Glenn Howerton plays as Dennis Reynolds in A.P. Bio.
Glenn Howerton is the top #1 member of the cast and appears in 161 episodes.

Lyric Lewis plays as Stef in A.P. Bio.
Lyric Lewis is the top #2 member of the cast and appears in 34 episodes.

Mary Sohn plays as Mary in A.P. Bio.
Mary Sohn is the top #3 member of the cast and appears in 34 episodes.

Jean Villepique plays as Michelle in A.P. Bio.
Jean Villepique is the top #4 member of the cast and appears in 34 episodes.

Paula Pell (born April 15, 1963) is an American writer, actress, comedian, and producer. Pell is best known for her work as a writer for the NBC sketch comedy series Saturday Night Live from 1995 to 2020. For her work on SNL and 30 Rock, she has been recognized with a Primetime Emmy Award for Outstanding Writing for a Variety, Music or Comedy Program and six Writers Guild of America Awards. In 2019, Pell was honored with the Herb Sargent Award for Comedy Excellence.

Paula Pell plays as Gloria in A.P. Bio.
Paula Pell is the top #5 member of the cast and appears in 22 episodes.

Tucker Albrizzi is an American actor. He is best known for his roles as Tyler Duncan on Big Time Rush, Jake on Good Luck Charlie, Randall Snyder on American Vandal and Colin McConnell on A.P. Bio. He has appeared in such movies as I Am Number Four, Bridesmaids, Sicko, and Alvin and the Chipmunks: Chipwrecked

Tucker Albrizzi plays as Walter in A.P. Bio.
Tucker Albrizzi is the top #6 member of the cast and appears in 21 episodes.

Tom Bennett is a British actor, best known for his roles in David Brent: Life on the Road, A.P. Bio and Red Dwarf.

Tom Bennett plays as Miles in A.P. Bio.
Tom Bennett is the top #7 member of the cast and appears in 13 episodes.

Sari Arambulo is an actress.

Sari Arambulo plays as Grace in A.P. Bio.
Sari Arambulo is the top #8 member of the cast and appears in 13 episodes.

American stand-up comedian, writer and actor Patton Oswalt first began performing standup comedy in the late 1980s to early 1990s. After spending two seasons writing for MADtv, and starring in his own 1996 comedy special for HBO, he began performing in films and television shows.In January 2011, Oswalt released his first book, Zombie Spaceship Wasteland. Oswalt married writer Michelle Eileen McNamara on September 24, 2005. Their daughter, Alice Rigney Oswalt, was born on April 15, 2009.

Patton Oswalt plays as Matthew the Raven (voice) in A.P. Bio.
Patton Oswalt is the top #9 member of the cast and appears in 11 episodes.

Aparna Brielle is an American actress known for her roles in Jay and Silent Bob Reboot, AP Bio, and Boo, Bitch.

Aparna Brielle plays as Tina Mukerji in A.P. Bio.
Aparna Brielle is the top #10 member of the cast and appears in 8 episodes.