John Casimir Kleczka (May 6, 1885 – April 21, 1959) was a Polish American lawyer, judge, and Republican politician from Milwaukee, Wisconsin.

He later served as a Wisconsin circuit court judge in Milwaukee County for nearly 23 years.

Born in Milwaukee, Wisconsin, Kleczka attended the parochial schools.

He was a major judge advocate in the United States Army Reserves after the First World War.

Kleczka was elected as a Republican to the Sixty-sixth and Sixty-seventh congresses (March 4, 1919 – March 4, 1923) as the representative of Wisconsin's 4th congressional district, after taking the Republican nomination away from incumbent William J. Cary, who had been one of 50 representatives who voted against declaring war on Germany.