John William Merrow (August 15, 1874 – April 11, 1927) was a New York City theater architect.
After 1909, he was the architect of Frederick Freeman Proctor's 1,100-acre (4 km2) country estate, known as "Proctoria," in Central Valley, New York.
The estate was purchased during World War II by the United States Military Academy (USMA) at West Point, for use as a recreation center for cadets.
In 1973, the USMA transferred the estate's locally famous gatehouse complex (designed by Merrow) and the adjacent land to the Woodbury Historical Society in Highland Mills, New York.
In 1921, he designed the Theta Delta Chi fraternity house in Hanover, New Hampshire on the basis of plans created by Arthur Bradley Barnes.