Karl Weidel III (September 27, 1923 – January 31, 1997) was an American Republican Party politician from New Jersey, who served in the New Jersey General Assembly.
Weidel was born on September 27, 1923 in Trenton, New Jersey. His father, Karl Weidel, Jr., ran an insurance and real estate brokerage, established in 1915. He attended Trenton Catholic High School, Duke University, and Rutgers Law School. During World War II he joined the United States Navy and became a pilot. Upon his return from World War II, he entered the family business, taking over the insurance division in 1949.
Weidel was a resident of Pennington, Mercer County, New Jersey. He became the first Republican in a generation elected to the Mercer County Board of Chosen Freeholders in 1966. He was first elected to the New Jersey General Assembly in 1971. In the New Jersey General Assembly he worked on no-fault insurance reform and also supported the "right-to-die" movement during the Karen Ann Quinlan case.
Weidel resigned from the Assembly in 1986 to take a position as executive director of the Unsatisfied Claim and Judgment Fund in the New Jersey Department of Insurance. His vacant seat was filled by C. Richard Kamin. Weidel retired from state government in 1990.