Karel Blažej Kopřiva (or Karl Blasius Kopriva; 9 February 1756 in Cítoliby – 15 May 1785 in Cítoliby) was a Czech organist and composer from a family of musicians.
Kopřiva studied first with his father, the composer Václav Jan Kopřiva (1708–1789), and later with Josef Seger in Prague. Then he became organist at the St. Jacob's Church in Cítoliby. He is especially renowned for his numerous concertos and fairs.