Vanhojentanssit or wanhojentanssit in Finnish (English: "ball of the (new) seniors"), de äldstes dag in Swedish (English: "day of the (new) seniors"), is a formal prom held in Finnish upper secondary schools (lukio) during the second year. It is a celebration of when the second-year students (of the three-year lukio) become the seniors of the school. The prom is usually held the day after the third-year students (the seniors) stop attending school and start studying for their matriculation exams in February. The people attending the dances are called vanhat ("seniors"). Sometimes the first word is spelled with a w for a more archaic feel.
After the ball, the students sometimes attend a dinner in the evening, which is sometimes in a very formal restaurant.