The Massachusetts Constitutional Convention of 1853 met from May 4 to August 2 in order to consider changes to the Massachusetts Constitution. This was the third such convention in Massachusetts history, following the original constitutional convention, in 1779–80 and the second, in 1820–21, which resulted in the adoption of the first nine amendments.
The 1853 convention was dominated by the waning Democratic-Free Soil coalition and proposed an entirely new constitution and seven separate provisions, which could be passed with or without the core constitution. The primary point of contention was the reallocation of political representation in the state; the coalition proposed a maintenance of the town representative system, while the Whigs proposed a proportional representation system that would be dominated by the cities. Every proposal was rejected narrowly by popular referendum, although a number of individual ideas arising from the convention were later adopted by individual amendment processes.
Since 1853, Massachusetts has had one subsequent constitutional convention, in 1917–1918.