The Commonwealth of the Philippines was the political designation of the Philippines from 1935 to 1946 when the country was a commonwealth of the United States. Before 1935, the Philippines was an insular area with non-commonwealth status; it had been a U.S. territory since the 1898 Treaty of Paris, following the Spain's loss of the Philippines in the Spanish-American War. The Commonwealth of the Philippines was envisioned as a transition government to rule for 10 years, preparatory to full Philippine independence. The Commonwealth was established after the acceptance by the Philippine Legislature of the Philippine Independence Act, popularly known as the Tydings-McDuffie Act. The law authorized the drafting of a constitution for the Philippines, by a popularly-elected constitutional convention. Upon the ratification of the constitution by the Filipino people, it would then be submitted to the President of the United States who would certify its having met certain requirements in the Independence Act.

Thereafter, the Filipino people would then be permitted to elect their own government with widely-expanded powers: virtually full autonomy. However foreign affairs, currency, and defense, would remain under the purview of the United States. In October, 1935, Filipinos held the first national election in their history, to select a chief executive (to be known as the President of the Philippines), a vice president, and the members of a unicameral national assembly. The first president of the Commonwealth was Manuel L. Quezon.

The Commonwealth embarked on a period of extremely ambitious efforts to set the stage for independence. It was hailed at the time as the first example of a colony being voluntarily relinquished by the occupier. Its nation-building efforts were widely studied by independence activists in South East and East Asia. The preparations for national defense, a more robust national economy, and the first efforts to build an independent foreign policy were hampered by the increasingly deteriorating diplomatic conditions of South East Asia at the time, and increasing political and economic disaffection locally. A proper evaluation of the effectiveness or failures of the ambitious nation-building schemes of the Commonwealth's pre-war government is made difficult by the conquest of the Philippines by the Empire of Japan which invaded during World War II. The Philippine government had its army drafted into the service of the United States, and the Japanese conquest precipitated the establishment of a Commonwealth government-in-exile upon the invitation of the United States government. The Commonwealth of the Philippines was accorded membership in the United Nations and was considered part of the Allied cause. After the reconquest of much of the Philippines by American and Allied forces, the U.S. restored the Commonwealth to its duties in February, 1945. Under the provisions of the Philippine Independence Act, U.S. President Harry S. Truman issued a proclamation recognizing the independence of the Philippines, which was officially recognized as the Republic of the Philippines a on July 4, 1946. The Commonwealth of the Philippines constitution remained in effect until 1973. It marked the transtion of the nomenclature of the Philippines from the colonial plural ("Islas Filipinas" and "Philippine Islands" of the Spanish and American colonial periods), to the unitary singular, "Philippines" as a sign of unity, sovereignty, and national identity.