Oper may refer to:
Technology Operator (disambiguation) IRC operator
Opera Deutsche Oper Berlin, Oper Leipzig, Komische Oper Berlin, Alte Oper Romantische Oper, genre of German opera
Surname Andres Oper, Estonian football player
Mathematics Oper (mathematics), a mathematical bundle on a punctured disc, equipped with a flat connection and an additional extra structure, called the "oper structure"