KSI (disambiguation)

KSI (born 1993; Olajide Olatunji) is an English YouTube personality, musician and professional boxer.

KSI or Ksi may also refer to:


 * Killed or Seriously Injured, in road safety
 * Kontoret för särskild inhämtning ("Office for Special Collection"), a Swedish intelligence agency
 * The Korean Studies Institute, a research institution on Korean studies in South Korea
 * KSI Industries, a fictional company in Transformers: Age of Extinction
 * KSI, IATA code for Kissidougou Airport in Guinea
 * Knattspyrnusamband Íslands (Football Association of Iceland), Icelandic sports group
 * ksi (unit), kilopound per square inch, a non-SI unit of stress or pressure
 * Ksi (Cyrillic), a letter of the early Cyrillic alphabet (Ѯ, ѯ) derived from the Greek letter Xi