Blas Parera (1777–1840) was a Spanish music composer and teacher. He lived his part of his life in Buenos Aires.
He was born in Murcia, Spain to two Catalan parents. In 1797, he moved to Buenos Aires. He contributed in the defence of the port of Buenos Aires during the British invasions of the Río de la Plata. He composed the music of the Argentine National Anthem, written by Vicente López y Planes in 1813. It was known as the Marcha Patriotica.
On 14 October 1809, in the church of San Nicolás de Bari, he married one of his students, Facunda del Rey. She was a fifteen-year-old orphan who lived in the Home for the Founding Children, where she sang in the choir.
He went back to Spain briefly after, and died in Mataró in poverty on 7 January 1840.