The North Lexington Street Historic District is a residential historic district at 508–536 North Lexington Street in Waltham, Massachusetts. It consists of a cluster of four houses and their associated outbuildings, built around the turn of the 20th century, and unusual for its state of cohesion and preservation given the busy nature of Lexington Street. Three houses are Colonial Revival in styling, and 528 Lexington is an 1873 Second Empire house. The house at 508 Lexington was built in 1865 and extensively restyled in 1905; it retains some Italianate styling. Particularly rare in Waltham is the converted barn at 526 Lexington Street. This cluster of buildings was traditionally associated with the Piety Corner area, but is now separated from it by a significant number of more modern buildings.