Aldo Junior Simoncini (born 30 August 1986) is a former Sammarinese footballer who played as a goalkeeper.
At the age of 19 his career was nearly ended after he suffered serious injuries in a car crash.
Simoncini was signed by Italian club Cesena in 2011. In January 2012 he was signed by Valenzana on a loan deal.
Simoncini and his twin brother, Davide, both scored an own goal each against Sweden on 7 September 2010, becoming the first twins to accomplish such a feat in an international competition.
Simoncini combined his football career with a job as an accountant, and also as a computer engineer.