The Hudson Armory is a former Massachusetts Army National Guard armory and training center located at 35 Washington Street in Hudson, Massachusetts, United States. It is a castle-like, two-story brick masonry building built in 1910 at the intersection of Park Street and Washington Street in Hudson along the Assabet River. It was originally constructed for the Massachusetts Volunteer Militia. It was designed by architects James E. McLaughlin and James Mulcahy. As of June 2021, there are plans to convert the currently vacant armory into a community arts center.