Chetirideset machenitsi") is a medieval Eastern Orthodox church constructed in 1230 in the town of Veliko Tarnovo in Bulgaria, the former capital of the Second Bulgarian Empire.

On the western addition some of the outer decoration survived revealing the traditional arches and coloured small ceramic plates inserted into the wall.

The church, dedicated to the Forty Martyrs of Sebaste, was built and painted on the order of Bulgarian tsar Ivan Asen II in honour of his important victory near Klokotnitsa over the Despotate of Epirus under Theodore Ducas on 9 March 1230.

After extensive reconstruction works, the Holy Forty Martyrs Church was fully renovated in the 2000s and opened once again to the public, with an official inauguration on 14 September 2006.

The Forty Martyrs Church was also the location of then-Prime Minister of Bulgaria Stefan Stambolov's lavish wedding to Polikseniya Kostaki Stanchova on 18 May 1888.