Trstenjak is a Slovenian surname. Notable people with the surname include:
Anton Trstenjak (1906–1996), Slovenian psychologist, theologian and authorAnte Trstenjak (1894–1970), Slovenian psychologist, painter and illustratorDavorin Trstenjak (1817–1890), Slovenian writer, historian and Roman Catholic priestTina Trstenjak (born 1990), Slovenian judokaVerica Trstenjak (born 1962), Slovenian lawyer and judge