The Keuffel and Esser Co. (also known as K&E) was a drafting instrument and supplies company founded in 1867 by German immigrants William J. D. Keuffel and Herman Esser.

Keuffel and Esser started out in New York and sold drawing materials and drafting supplies. In 1876, K&E (as the company was known) started selling surveying instruments. A four-story factory in Hoboken, New Jersey was completed four years later, and K&E was incorporated in 1889.

In the following decade Keuffel and Esser introduced another, new line of surveying instruments based on the work of John Paoli, an Italian immigrant in Hoboken.

K&E acquired Young & Sons in 1918 and made it a department of the firm. In the 1920s, K&E started manufacturing slide rules. In World War II the company made fire-control instruments for the US Government and won three Army-Navy ‘E’ Awards for Excellence in Production.

However, with the advent of the electronic, transistorized calculator in the 1970s, slide rules became obsolete in most contexts. Slide rules had never been very profitable for K&E, so it was not difficult to discontinue the line. K&E's market share shrank due to other technological advancements and the firm shut down its slide rule engraving machines in 1975.^[1]

Keuffel and Esser had an office in Montreal, at 130 Montée de Liesse, in the 1960's.

K&E was acquired by AZON Corp. in 1987.