The term one-child policy refers to a population planning initiative in China implemented between 1980 and 2015 to curb the country's population growth by restricting many families to a single child. That initiative was part of a much broader effort to control population growth that began in 1970 and ended in 2021, a half century program that included minimum ages at marriage and childbearing, two-child limits for many couples, minimum time intervals between births, heavy surveillance, and stiff fines for non-compliance. The program had wide-ranging social, cultural, economic, and demographic effects, although the contribution of one-child restrictions to the broader program has been the subject of controversy.

China's family planning policies began to be shaped by fears of overpopulation in the 1970s, and officials raised the age of marriage and called for fewer and more broadly spaced births. Overpopulation, in the eyes of the state officials, would hinder their agenda to boost the national economy and improve people's standard of living. After a full decade of concerted efforts, a near universal one-child limit was imposed in 1980. It was then officially written into the constitution of the PRC in 1982. In 2015, the government removed all remaining one-child limits, establishing a two-child limit. In May 2021, this was loosened to a three-child limit, in July 2021 all limits as well as penalties for exceeding them were removed.

The strictness with which it was enforced varied by period, region, and social status. In some cases, women were forced to use contraception, receive abortions, and undergo sterilization. Families who violated the policy faced large fines and other penalties, such as firings and restrictions for future careers.