For most of Portugal's history, few non-Catholics lived in the country those who did could not practice their religion freely. Until the constitution of 1976 was enacted, laws restricted the activities of non-Catholics. By the early 1990s, only some 50,000 to 60,000 Protestants lived in Portugal, about 1 percent of the total population. They had been kept out of the country for three centuries by the Inquisition. However, the British who began settling in Portugal in the nineteenth century brought their religions with them. Most belonged to the Church of England, but others were Methodists, Congregationalists, Baptists, and Presbyterians. Protestantism remained largely confined to the foreign communities. The 1950s and 1960s saw the arrival of Pentecostals, Mormons, and Jehovah's Witnesses, all of whom increased in numbers more rapidly than the earlier arrivals did. All groups, however, were hampered by prohibitions and restrictions against the free exercise of their religions, especially missionary activities.

These restrictions were lifted after the Revolution of 1974. The constitution of 1976 guarantees all religions the right to practice their faith. Protestant groups came to be recognized as legal entities with the right to assemble. Portuguese who were both Protestant and conscientious objectors had the right to apply for alternative military service. The Roman Catholic Church, however, still sought to place barriers in the way of Protestant missionary activities.

The Jewish community in Portugal numbered between 500 and 1,000 as of the early 1990s. The community was concentrated in Lisbon, and many of its members were foreigners. The persecution of Portuguese Jewry had been so intense that until recent decades Portugal had no synagogue or even regular Jewish religious services. The few Jewish Portuguese were hence isolated from the main currents of Judaism. Their community began to revive when larger numbers of foreign Jews (embassy personnel, business people, and technicians) began coming to Portugal in the 1960s and 1970s. In northern Portugal, there were a few villages of Marranos, descendants of Jews who converted to Christianity to avoid persecution and whose religion was a mixture of Judaism and Christianity. Portugal's Muslim community consisted of a small number of immigrants from Portugal's former colonies in Southern Africa, and larger numbers of recent immigrant workers from Northern Africa, mainly Morocco.

Data as of January 1993