Viktor Emil Frankl (Austrian German: ; 26 March 1905 – 2 September 1997)was an Austrian neurologist, , philosopher, and Holocaust survivor, who founded logotherapy, a school of psychotherapy that describes a search for a life's meaning as the central human motivational force. Logotherapy is part of existential and humanistic psychology theories.

Logotherapy was promoted as the third school of Viennese Psychotherapy, after those established by Sigmund Freud and Alfred Adler.

Frankl published 39 books. The autobiographical Man's Search for Meaning, a best-selling book, is based on his experiences in various Nazi concentration camps.