Alfred Dennis Sieminski (August 23, 1911 – December 13, 1990) was an American Democratic Party politician who represented New Jersey's 13th congressional district, centered on Hudson County, in the United States House of Representatives for four terms from 1951 to 1959.

[2] He worked as comptroller and vice president of Brunswick Laundry in Jersey City starting in 1937.

He entered the United States Army as a private in 1942, served in the Italian Campaign with the 92nd Infantry Division in 1944 and 1945, was a captain, Military Government Division in Austria, in 1945 and 1946, served with Tenth Corps in Korea in 1950, was discharged to the Infantry Reserve as a major in 1950 and promoted to lieutenant colonel in 1956.

To date, he is the last incumbent New Jersey congressman to lose in a non-redistricting primary election.

Sieminski was a resident of Vienna, Virginia, until his death on December 13, 1990, at the age of 79 due to a heart attack.