Friendly Rivalry

Original Creator

• 
  Song Chae Yun

Screenwriter

• 
  Min Ye Ji

Screenwriter & Director

• 
  Kim Tae Hui

Main Role

• 
  Lee Hye Ri

  Yoo Je I

  Main Role
• 
  Chung Su Bin

  Woo Seul Gi

  Main Role
• 
  Kang Hye Won

  Ju Ye Ri

  Main Role
• 
  Oh Woo Ri

  Choi Gyeong

  Main Role

Support Role

• 
  Choi Young Jae

  Nam Byeong Jin

  Support Role
• 
  Kim Tae Hoon

  Yoo Tae Jun [Je I's father]

  Support Role
• 
  Chae Seo Eun

  Cho A Ra

  Support Role
• 
  Kim Sang Ji

  Kim Beom Su

  Support Role
• 
  Kang Jin Ah

  Kwon Hui Yun

  Support Role
• 
  Ma Hyun Ji

  Park Byeong Hui

  Support Role
• 
  Choo Ye Jin

  Yoo Je Na

  Support Role
• 
  Ha Min

  [Principal]

  Support Role
• 
  Yoo Ha Young

  Choi Su Jin

  Support Role
• 
  Kim Yu Bin

  Bae Yeon Seo

  Support Role
• 
  Han Ri I

  Lee Si U

  Support Role
• 
  Go Seo Hee

  Nam Ji Yeon

  Support Role
• 
  Koh Da Hyeon

  Kim Na Ri

  Support Role
• 
  Lah Hyun Jin

  Koo Chae Ryeong

  Support Role

Guest Role

• 
  Lee Eun Ju

  [Nun] (Ep. 1)

  Guest Role
• 
  Son Yeong Soon

  [Flower seller] (Ep. 1)

  Guest Role
• 
  Park Seong Kyun

  [Security guard] (Ep. 1)

  Guest Role
• 
  Oh Eun Seo

  Yoo Je I [Young] (Ep. 3)

  Guest Role
• 
  Park Soo Jin

  [Coach] (Ep. 3)

  Guest Role
• 
  Gi So Yoo

  Yoo Je Na [Young] (Ep. 3, 9)

  Guest Role
• 
  Lee Jae Joon

  Jung Ha Jin (Ep. 5)

  Guest Role
• 
  Seo Yeon Woo

  Im Hyeon Ji (Ep. 5)

  Guest Role
• 
  Song A Kyung

  [Music professor] (Ep. 5)

  Guest Role
• 
  Jung Il Hwa

  [Choi Gyeong's teacher] (Ep. 5)

  Guest Role
• 
  Moon Ki Young

  [Doctor] (Ep. 6)

  Guest Role
• 
  Jun Joon Woo

  [Psychiatrist] (Ep. 6)

  Guest Role
• 
  Yoon Chae Na

  Ju Ye Ri [Young] (Ep. 7)

  Guest Role
• 
  Jo Eun Joo

  [Host club worker] (Ep. 7)

  Guest Role
• 
  Lee Seol A

  Yoo Je Na [Teen] (Ep. 9)

  Guest Role
• 
  Min Sang Chul

  [Lawyer] (Ep. 10)

  Guest Role
• 
  Kim Won Seok

  [Detective] (Ep. 10)

  Guest Role
• 
  Choi Ri Ho

  [Beom Su's father] (Ep. 10)

  Guest Role
• 
  Choi Ga In

  [Beom Su's mother] (Ep. 10)

  Guest Role
• 
  Lee Woo Joo

  Yoo Tae Jun [Teen] (Ep. 11)

  Guest Role
• 
  Im Jun Hyeong

  [Nightclub bouncer] (Ep. 11)

  Guest Role
• 
  Jung Yong Hee

  [Nursing home doctor] (Ep. 12)

  Guest Role
• 
  Kim Hak Soo

  [Security staff] (Ep. 13)

  Guest Role
• 
  Kwon Hyuk Soo

  [Tae Jun's father] (Ep. 13)

  Guest Role
• 
  Park Geon Rak

  [Tae Jun's brother] (Ep. 13)

  Guest Role
• 
  Yoon Woo Ri

  [Woman buying drugs] (Ep. 13)

  Guest Role
• 
  Park Sang Hwi

  [Lawyer] (Ep. 14)

  Guest Role
• 
  Hong Dae Sung

  [Mechanic] (Ep. 14)

  Guest Role
• 
  Song Chae Yun

  Song Jae Hui (Ep. 16)

  Guest Role
• 
  Lee Dong Gyu

  [Anchor] (Ep. 16)

  Guest Role
• 
  Kim Geu Lim

  Son Mi Yeong

  Guest Role
• 
  Bae Hyun Kyung

  Park Min Gyu

  Guest Role
• 
  Lee Won Jae

  Woo Do Hyeok

  Guest Role
• 
  Lee Joo Yeon

  Yoo Je I [Young teen]

  Guest Role
• 
  Joo Ye Rim

  Choi Gyeong [Young]

  Guest Role
• 
  Park Min Young

  [Je I's mother]

  Guest Role
• 
  Lee Na Ra

  [Ye Ri's mother]

  Guest Role
• 
  Seo Hye Jin

  [Bubble manager]

  Guest Role
• 
  Choi Ha Yoon

  Woo Seul Gi [Child]

  Guest Role
• 
  Moon Seo Hyeon

  Woo Seul Gi [Teen]

  Guest Role
• 
  Kim Tae Geun

  Park Myeong Ho (Ep. 15-16)

  Guest Role
• 
  Choi Yeon Hwa

  [Institute teacher] (Ep. 2)

  Guest Role
• 
  Park Gi Seon

  [Judge] (Ep. 14)

  Guest Role
• 
  Lee Eo Jin

  Kim Mi Yeon (Ep. 2)

  Guest Role
• 
  Hong Hyun Ho

  [Hostel manager] (Ep. 12)

  Guest Role
• 
  Lim Su Hwan

  [Chief of administration]

  Guest Role
• 
  Kim Bom

  [Middle school bully] (Ep. 1)

  Guest Role

Unknown

• 
  Bae Yoon Unknown