Isaac Whitbeck Van Schaick (December 7, 1817 – August 22, 1901) was an American businessman and Republican politician.

After the American Civil War, Van Schaick traveled to Arkansas and worked for in the cotton industry.

Van Schaick was elected as a Republican to the Forty-ninth Congress in 1884 as the representative of Wisconsin's 4th congressional district.

He declined to be a candidate for renomination in 1886, and was succeeded by Henry Smith of the Union Labor Party.

Van Schaick defeated Smith for election to the 51st United States Congress in 1888, receiving 22,212 votes to 20,685 for Smith (running on the Democratic and Labor tickets), 527 for Socialist John Schuler and 302 for Prohibitionist George Heckendorn.