Celltrion, Inc. (Korean: 주식회사 셀트리온) is a biopharmaceutical company headquartered in Incheon, South Korea. Celltrion Healthcare conducts worldwide marketing, sales, and distribution of biological medicines developed by Celltrion. Celltrion's founder, Seo Jung-jin, is the richest person in South Korea. Seo Jung-jin, its founder was awarded the 2021 EY World Entrepreneur Of The Year.

In 1999, Nexol, Inc. (now Celltrion Healthcare Co., Ltd.) was founded as a global business management consulting firm. In 2002, Celltrion, Inc. was founded as a biopharmaceutical company.

In 2008, Nexol and Celltrion established a global distribution agreement.

In 2009, distribution channels were established in America, Oceania, Europe (Hospira) and Nexol, Inc. renamed as Celltrion Healthcare Co., Ltd.

In 2010, distribution channels were established in Japan (Nippon Kayaku), Commonwealth of Independent States (CIS), Eastern Europe, and the Middle East (Egis).

In 2013, distribution channels were added in Europe (Mundipharma, Biogaran, and Kern).

In September 30, 2024, Celltrion completed the establishment of its oversees corporation in Vietnam. 22 Oct. 2024. Celltrion secured a 100.4 billion won ($72.8 million) deal for contract development and manufacturing (CDMO) with TEVA Pharmaceuticals International for the migraine treatment Ajovy.

In November 2024, Celltrion acquired iQone Healthcare Switzerland, a pharmaceutical company for around 30 billion won ($21 million). This move will help its expansion in Europe.