Kazimierz Wojniakowski was a Polish painter, illustrator and Freemason, known primarily for his portraits in the sentimentalist style.

He was a pupil of Marcello Bacciarelli.

His work as a portraitist was influenced by that of the Austrian painter Josef Grassi (who was living in Warsaw at that time), as exemplified in his 1796 Portrait of Izabela Czartoryska, née Fleming.

Other noteworthy portraits by Wojniakowski include Tadeusz Kościuszko, Stanisław August Poniatowski and Stanisław Sołtyk.

He also produced religious works and scenes of contemporary historic events (e.g., The Constitution of May 3, 1791, 1806).

Notable as well are his drawings from journeys, e.g. in Lublin Province.