The Senate of Puerto Rico is the upper house of the Legislative Assembly of Puerto Rico, the territorial legislature of Puerto Rico. The Senate, together with the House of Representatives of Puerto Rico, control the legislative branch of the government of Puerto Rico.

The Constitution of the Commonwealth of Puerto Rico is the controlling government document of Puerto Rico. It is composed of nine articles detailing the structure of the government as well as the function of several of its institutions. The document also contains an extensive and specific bill of rights. It was ratified by Puerto Rico's electorate in a referendum on March 3, 1952, and on July 25, 1952, Governor Luis Muñoz Marín proclaimed that the constitution was in effect. July 25 is known as Constitution Day.