Ko Sung-hee (Hangul: 고성희; born June 21, 1990) is a South Korean actress. She is best known for her leading roles in Diary of a Night Watchman (2014) and My Holo Love (2020). She has also starred in While You Were Sleeping (2017) and Mother (2018).

• 분노의 윤리학 (2013)

  
• While You Were Sleeping (2017)

  
• The Night Watchman (2014)

  
• Suits (2018)

  
• My Holo Love (2020)