The American Watch Tool Company is a historic factory complex at 169 Elm Street in Waltham, Massachusetts.

[1] The American Watch Tool Company complex is located on the west side of Elm Street, a short way south of the Charles River.

The largest building, dating to 1901, stands closest to the street; it is seven bays wide, six of which have windows set in segmented-arch openings at the two main levels, with smaller similar windows at the basement level.

[2] The American Watch Tool Company was established as a spinoff of the American Watch Company, Waltham's leading business of the late 19th century.

This facility was used in that business until 1904, expanding the premises in 1879 and 1882. and was thereafter used by the Metz Company for the manufacture of automobiles.