István Lanstyák (born 13 July 1959 Lučenec) is an Hungarian linguist.He studied at the University of Debrecen.István Lanstyák received his PhDr. in 1989 and PhD. in 1995 at the Comenius University in Bratislava. He teaches at Comenius University and publishes in the areas of Sociolinguistics Multilingualism Language planning and Code-switching.