| Honorific-Prefix: | The Honourable |
| Camilo Osías | |
| Order: | 6th |
| Office: | President of the Senate of the Philippines |
| President: | Elpidio Quirino |
| Appointer: | Senate |
| Term Start: | April 30, 1953 |
| Term End: | May 20, 1953 |
| Predecessor: | Eulogio Rodriguez |
| Successor: | Jose Zulueta |
| President2: | Elpidio Quirino |
| Appointer2: | Senate |
| Term Start2: | April 17, 1952 |
| Term End2: | April 30, 1952 |
| Predecessor2: | Quintin Paredes |
| Successor2: | Eulogio Rodriguez |
| Office3: | Senator of the Philippines |
| Term Start3: | December 30, 1947 |
| Term End3: | December 30, 1953 |
| Term Start4: | December 30, 1961 |
| Term End4: | December 30, 1967 |
| Term Start5: | 1925 |
| Term End5: | 1929 |
| Alongside5: | Alejo Mabanag (1925-1928) Teofilo Sison (1928-1929) |
| Constituency5: | 2nd district |
| Predecessor5: | Bernabé de Guzmán |
| Successor5: | Alejandro de Guzmán |
| Office6: | Minister of Education |
| President6: | José P. Laurel |
| Term Start6: | October 1943 |
| Term End6: | February 1945 |
| Predecessor6: | Claro M. Recto |
| Office7: | Member of the Philippine National Assembly from La Union's 1st district |
| Term Start7: | November 15, 1935 |
| Term End7: | 1938 |
| Predecessor7: | Francisco Ortega |
| Successor7: | Delfin Flores |
| Office8: | Resident Commissioner to the U.S. House of Representatives from the Philippine Islands |
| Term Start8: | March 4, 1929 |
| Term End8: | January 3, 1935 |
| Predecessor8: | Isauro Gabaldon |
| Successor8: | Francisco A. Delgado |
| Alongside8: | Pedro Guevara |
| Birth Name: | Camilo Osías y Olaviano |
| Birth Date: | 23 March 1889 |
| Birth Place: | Balaoan, La Union, Captaincy General of the Philippines |
| Death Place: | Manila, Philippines |
| Party: | Liberal (1953–1976) |
| Otherparty: | KALIBAPI (1942–1945) Nacionalista (1925–1942; 1947–1953) |
| Spouse: | Ildefonza Cuaresma Avelina Lorenzana |
| Children: | 6 |
| Alma Mater: | University of Chicago Western Illinois University Columbia University |
Camilo Olaviano Osías Sr. (March 23, 1889 – May 20, 1976), was a Filipino politician, twice for a short time President of the Senate of the Philippines. Along with American Mary A. Lane, Osías translated into English the poem Filipinas that was set to the Marcha Nacional Filipina, producing the Philippine Hymn, now the national anthem Lupang Hinirang.
Osías attended school in Balaoan, Vigan and San Fernando, and was selected a government scholar to the United States in 1905. He studied at the University of Chicago in 1906 and 1907. He graduated from the Western Illinois State Teachers College at Macomb, Illinois in 1908, and from the Teachers College of Columbia University in New York City in 1910.
On his return to the Philippines, he taught and later assumed various administrative positions, particularly in the field of education. He successively became the first Filipino Superintendent of Schools (1915 to 1916), Assistant Director of Education (1917 to 1921), a lecturer at the University of the Philippines (1919 to 1921), and President of National University (1921–1936), a private institution.
Osías then entered national politics. He was a member of the first Philippine mission to the United States (1919 to 1920). He was elected to the Philippine Senate in 1925, and as a Nacionalista, was Resident Commissioner in the United States House of Representatives in 1928, reelected in 1931 and served from March 4, 1929 until January 3, 1935, when his term expired in accordance with the new government of the Philippine Commonwealth. In 1934, he was an unsuccessful candidate for election to the Philippine Senate, but became a member of the Constitutional Convention in 1934, and a member of the first National Assembly in 1935. In 1939, he was a member of the Economic Mission to the United States, and chairman of the Educational Mission between 1938 and 1941.
Back in the Philippines, Osías became chairman of the National Council of Education in 1941, Director of Publicity and Propaganda until January 1942, chairman of the National Cooperative Administration in 1941, later Assistant Commissioner of the Department of Education, Health, and Public Welfare, then Secretary of Education until 1945. He was also Chancellor of Osías Colleges. He was elected again to the Philippine Senate in 1947 for a term expiring in 1953. He was President of the Senate of the Philippines twice for a short time in 1952 and in 1953. He was the Philippines' representative to the Inter-Parliamentary Union in Rome and to the International Trade Conference in Genoa in 1948. He ran as a Nacionalista again, this time for President of the Philippines, in 1953 and lost to Ramón Magsaysay. He was again elected, this time as a Liberal to the Philippine Senate (1961–1967), and served as president pro tempore. He was a resident of Mandaluyong, Rizal (since incorporated into Metro Manila), until his death.
Osías was married to Ildefonsa Cuaresma, a former public school teacher from Bacnotan, near his hometown, in 1914. The couple raised seven children, Camilo Jr., Salvador, Victor, Apolinario, Rebecca, Benjamin and Rosita. After more than 20 years of marriage, Camilo divorced Ildefonsa and married Avelina Lorenzana in Reno, Nevada. That marriage produced no children.