Inclusion Criteria:  Study participant must be at least 19 years of age at the time of signing the informed consent Study participant must be a Korean adult with a diagnosis of moderate to severe psoriasis (PSO) Study participant must have had plaque PSO for at least 6 months prior to the Screening Visit Study participant must have Psoriasis Area and Severity Index (PASI) ≥12 and body surface area (BSA) affected by PSO ≥10% and Investigator's Global Assessment (IGA) score ≥3 on a 5-point scale Study participant must be a candidate for systemic PSO therapy and/or phototherapy Study participant agrees not to change their usual sun exposure during the course of the study and to use ultraviolet A/ultraviolet B sunscreens if unavoidable exposure occurs A female study participant is eligible to participate if she is not pregnant, not breastfeeding, and at least one of the following conditions applies: Not a female of childbearing potential (FOCBP) OR A FOCBP who agrees to follow the contraceptive guidance during the Treatment Period and for at least 20 weeks after the last dose of study treatment  Exclusion Criteria:  Subject has an active infection (except common cold), a serious infection, or a history of opportunistic or recurrent chronic infections Subject has concurrent acute or chronic viral hepatitis B or C or human immunodeficiency virus (HIV) infection Subject has known tuberculosis (TB) infection, is at high risk of acquiring TB infection, or has current or history of nontuberculous mycobacterium (NTMB) infection Subject has any active malignancy or history of malignancy within 5 years prior to the Screening Visit EXCEPT treated and considered cured cutaneous squamous or basal cell carcinoma, or in situ cervical cancer Study participant has a presence of active suicidal ideation or positive suicide behavior Study participant has a presence of moderately severe major depression or severe major depression Subject has a known hypersensitivity to any excipients of bimekizumab Subject has any other condition, including medical or psychiatric, which, in the Investigator's judgment, would make the subject unsuitable for inclusion in the study