Study of Guselkumab in Skin of Color Participants With Moderate-to-severe Plaque and/or Scalp Psoriasis

The purpose of this study is to evaluate the efficacy of guselkumab treatment versus placebo in skin of color participants with predominant moderate-to-severe body psoriasis or predominant moderate-to-severe scalp psoriasis by assessing improvements in the signs and symptoms of psoriasis.

Inclusion Criteria: * Have a diagnosis of plaque psoriasis (with or without psoriatic arthritis \[PsA\]) for at least 6 months before the first administration of study drug * Self-identify as non-white or non-caucasian * Be a candidate for phototherapy or systemic treatment for psoriasis * Have an involved body surface area (BSA) greater than or equal to (\>=) 10 percent (%), psoriasis area and severity index (PASI) \>=12, investigator global assessment (IGA) \>=3 at screening and at baseline (Cohort A), or have a scalp surface area \>=30%, psoriasis scalp severity index (PSSI) \>=12, scalp specific investigator global assessment (ss-IGA) \>=3, and one plaque outside of the scalp at screening and at baseline (Cohort B) * Agree not to receive a live virus or live bacterial vaccination during the study, or within 12 weeks after the last administration of study intervention * Agree not to receive a Bacillus Calmette-Guérin (BCG) vaccination during the study, and within 12 weeks after the last administration of study intervention Exclusion Criteria: * Has a nonplaque form of psoriasis (example: erythrodermic, guttate, or pustular) * Has received ustekinumab, ixekizumab, secukinumab, or brodalumab within 12 weeks of first dose of study drug * Has a history or current signs or symptoms of severe, progressive, or uncontrolled renal, cardiac, vascular, pulmonary, gastrointestinal, endocrine, neurologic, hematologic, rheumatologic, psychiatric, or metabolic disturbances * Participant has known allergies, hypersensitivity, or intolerance to guselkumab or its excipients * Has or has had a serious infection (example: sepsis, pneumonia or pyelonephritis), or has been hospitalized or received intravenous antibiotics for an infection during the 2 months before screening