Lajos Kassák (March 21, 1887, Érsekújvár – July 22, 1967, Budapest) was a Hungarian poet, novelist, painter, essayist, editor, theoretician of the avant-garde, and occasional translator. He was among the first genuine working-class writers in Hungarian literature. Self-taught, he became a writer within the socialist movement and published journals important to the radical intellectual culture of Budapest in the early 1900s.
Lajos Kassák was born in Érsekújvár, Austria-Hungary (present-day Nové Zámky, Slovakia). His father was an apothecary assistant and his mother a laundress. Although his parents wanted him to attend higher education, he decided to quit his studies and started work as a locksmith assistant, gaining a letter of indenture as an apprentice. His sister was Erzsi Újvári who went on to marry Sándor Barta.