This thesis explored the use of ideology as defined by Spolsky and Woolard and Schieffelin to explain both the Japanese and Kuomintang regimes use of language policy in Taiwan from 1895 to 1987. In the case of the Japanese, they introduced both educational reform and a new language into Taiwan after 1895. It was their desire to see the Taiwanese become good citizens of the Empire. When the new government first arrived on the island the use of local dialects were still permitted, and local Chinese schools remained open for a time. During the later colonial period in Taiwan the use of the Japanese language became more and more dominant. In the case of the Kuomintang who came to govern Taiwan after 1945, it was their use of Mandarin that defined their form of language policy on the island. The KMT believed that they were the legal government of China and planned for their eventual return to the mainland.