John Nicholas Luff (November 16, 1860 – August 23, 1938) of New York City was one of the important philatelists of the late 19th and early 20th centuries, notable as an early user of scientific methods in the study of postage stamps.

He developed a serious interest in philately in 1890, and joined the Pacific Philatelic Society in San Francisco, California.

In 1896, he helped establish the Collectors Club of New York, and was later its president for a number of years.

Luff had become perhaps the most prolific philatelic writer of the age, with works ranging from the tutorial What Philately Teaches Us (1899) to the classic reference work The Postage Stamps of the United States (1902), and numerous articles in the AJP and Mekeel's Weekly Stamp News.

In 1913, Luff was one of 10 judges who participated in the Panama-Pacific Exposition[permanent dead link‍] held in San Francisco, CA.