Bandaranaike attempted to reform the former British Colony of Ceylon into a socialist republic by nationalizing organizations in the banking, education, industry, media and trade sectors. Changing the administrative language from English to Sinhala, she exacerbated discontent among the native Tamil population, and with the estate Tamils, who had become stateless under the Citizenship Act of 1948. During Bandaranaike's first two terms as Prime Minister, the country was plagued by high inflation and taxes, a dependence on food imports to feed the populace, high unemployment, and polarization between the Sinhalese and Tamil populations because of her Sinhalese nationalist policies. Surviving an attempted coup d'état in 1962, as well as a 1971 insurrection of radical youths, in 1972 she oversaw the drafting of a new constitution and the formation of the Sri Lankan republic. In 1975, Bandaranaike created what would eventually become the Sri Lankan Ministry of Women and Child Affairs, also appointing the first woman to serve in the Sri Lankan Cabinet. Bandaranaike's tenure was marked by inadequate economic development at the national level. She played a large role abroad as a negotiator and a leader among the Non-Aligned Nations.
Ousted from power in the 1977 elections, Bandaranaike was stripped of her civil rights in 1980 for alleged abuses of power during her tenure and barred from government for seven years. Her successors initially improved the domestic economy, but failed to address social issues, and led the country into a protracted civil war. When she returned to party leadership in 1986, Bandaranaike opposed allowing the Indian Peace Keeping Force to intervene in the civil war, believing it violated Sri Lankan sovereignty. Failing to win the office of President in 1988, she served as Leader of the Opposition in the legislature from 1989 to 1994. When her daughter won the presidential election that year, Bandaranaike was appointed to her third term as Prime Minister and served until her retirement in 2000, two months prior to her death.