Stefan Plewniak is a Polish conductor and violinist. He is the first conductor of the Opéra Royal de Versailles and former musical director of the Warsaw Chamber Opera. He is founder and musical director of the Il Giardino d'Amore orchestra and the Cappella dell'Ospedale della Pietà Venezia. In 2016, he founded The FeelHarmony symphony orchestra.

He began his studies with Barbara Sliwicka at the Krakow Academy of Music, and continued with Robert Szreder at the Maastricht Conservatoire and François Fernandez at the Paris Conservatoire. It was while working with the period-instrument ensemble Les Goûts Réunis that Stefan Plewniak developed an interest in Baroque violin.
Since then, he has performed with a number of period ensembles, including Cappella Cracoviensis, Contrasto Armonico, Ensemble Marguerite Louise, Orchestre 1756, Les Arts Florissants and Le Concert des Nations. He also performs with modern symphony orchestras such as the Warsaw Polish Radio Orchestra, the Krakow Philharmonic Orchestra and the Amsterdam Symphony Orchestra. He formed the ensemble Il Giardino d'Amore and has recorded Renaissance and Baroque repertoire with them on the Ëvoe label, of which he is founder and director.