The Joseph Loth Company Building is a historic industrial building at 25 Grand Street in Norwalk, Connecticut. It is a two-story brick Romanesque Revival structure with a four-story clock tower. The rear of the building has been altered by the addition of modern concrete sections in the 1950s. Built in 1903, it is a well-preserved example of industrial architecture of the period, and is a local landmark.
The building was listed on the National Register of Historic Places on May 17, 1984.