The Honourable Sir Casimir Stanislas Gzowski (1813-1898), served as acting Lieutenant Governor of Ontario from 1896 to 1897.

Gzowski was born in St. Petersburg to a noble Polish father who served with the Russian military. He emigrated with his family to the United States after the Polish revolt against Russia in 1830. Trained as an engineer, he was involved in railway construction in the United States,

Eventually he was hired as an engineer to help in the construction of the New York and Erie Railway. In 1841 he moved to Canada to work on the Welland Canal, and also helped finish the building of Yonge Street in southern Ontario. In 1853 he also helped build the Grand Trunk Railway. He was knighted in 1890, and briefly served as Lieutenant Governor before Oliver Mowat took power in 1897.

Gzowski was the great-grandfather of CBC radio personality Peter Gzowski.