Killian Van Rensselaer (June 9, 1763 - June 18, 1845) was an American lawyer and politician who served in the Congress of the United States as a Representative from the state of New York. He was the cousin of Jeremiah Van Rensselaer and the uncle of Solomon Van Vechten Van Rensselaer, who were also Representatives.
Van Rensselaer was born in East Greenbush, New York. He completed preparatory studies and attended Yale College, where he studied law. He was admitted to the bar in 1784, and commenced practice in Claverack, New York. He was private secretary to General Philip Schuyler.
Van Rensselaer was elected as a Federalist to the Seventh, Eighth, Ninth, Tenth, and Eleventh United States Congresses, serving from March 4, 1801 to March 3, 1811. Afterwards, he resumed the practice of law.
Van Rensselaer died in Albany, New York, and was interred in a private cemetery at East Greenbush.