Filipinization refers to the inclusion of Filipinos in the U.S. colonial government of the Philippines, particularly under Governor General Francis Burton Harrison. While there were 2,623 Americans and 6,363 Filipino superannuated officials in 1913 during the beginning of Harrison's tenure, there were 13,240 Filipinos and 614 Americans in 1921 when he left office. He also oversaw the transformation of the colonial legislature into a directly elected, Filipino-controlled body.
While Filipinization angered many conservative Americans, it was strongly supported by northern Catholic Filipinos, and Harrison was later granted Philippine citizenship when the nation was granted independence in 1935. However, Filipinization was strongly opposed by Muslim Moros living in the south of the country. They had not previously considered themselves to be Filipinos, and they feared the consequences of an independent Catholic Philippines, particularly because Filipinization resulted in Catholic settlers and administrators for Muslim lands.