Katherine Langford (born 29 April 1996) is an Australian actress. After appearing in several independent films, she had her breakthrough starring as Hannah Baker in the Netflix television series 13 Reasons Why (2017–2018), which earned her a Golden Globe Award nomination. She has gone on to appear in the films Love, Simon (2018) and Knives Out (2019), and headline the dark comedy Spontaneous (2020) and the Netflix series Cursed (2020).

Early life
Langford was born in Perth, Western Australia, and raised in Applecross, a riverside suburb of Perth. She is the eldest daughter of Elizabeth Langford (née Green), a paediatrician, and Stephen Langford, a flying doctor and director of medical services at the Royal Flying Doctor Service Western Operations. Her younger sister, Josephine Langford, is also an actress.

Langford began voice lessons with Heidi Lake in 2005, and received classical, jazz, and contemporary vocal training. She was offered a place at Perth Modern School for her senior high school years, where she studied music and drama, and was sports captain and a nationally ranked swimmer.

Initially during her time at high school, Langford was interested in medicine and politics in addition to musical theatre. In 2012 as a teenager, Langford attended a Lady Gaga concert, the Born This Way Ball, which inspired her to learn to play piano. She shared videos of herself singing three original songs she wrote: "I've Got a Crush on Zoe Bosch," "Young and Stupid," and "3 Words." "Young and Stupid" is an anti-suicide song she wrote in 2013 after three Perth teens took their lives. For her final year at Perth Modern, Langford stopped swimming and switched her focus to music and performance. She was successful in a number of musical eisteddfods and drama competitions. Langford appeared in the school's production of Hotel Sorrento in 2013 and graduated that same year.

From 2014 to 2015, Langford studied at the Principal Academy of Dance & Theatre Arts, majoring in Music Theatre, and appeared in a production of Godspell. She was then one of five students selected to participate in the National Institute of Dramatic Art (NIDA) Advanced Actors Residency in 2015. Additionally, Langford was provided a spot in Western Australian Academy of Programming. In the same year, she trained at Nicholson's Academy of Screen Acting and portrayed the role of Juan Perón's mistress in its 2015 production of Evita. Langford was offered a position in the Bachelor of Arts program in acting at the Western Australian Academy of Performing Arts and intended to begin studies in 2016. However, she never enrolled and instead pursued professional roles.