Armory Block is a historic block at 39-45 Park Street in Adams, Massachusetts. It is one of the four large brick buildings on Park Street along with the P. J. Barrett Block, Jones Block, and the Mausert Block, opposite the Town Hall. It was built in 1894 by A.J. Daniel, a developer from a locally prominent family. The building was built in c. 1895 to serve as an armory for the Massachusetts National Guard, a role it fulfilled until new facilities were built in 1914. After it was decommissioned from military use it was converted into commercial and retail space, uses which continue today. The building was listed on the National Historic Register in 1982.