Former Catholics or ex-Catholics are people who used to be Catholic for some time, but no longer identify as such. This includes both individuals who were at least nominally raised in the Roman Catholic faith, and individuals who converted to it in later life, both of whom later rejected and left it, or converted to other faiths (including the related non-Roman Catholic faiths). This page lists well-known individuals in history who are former Catholics.
One 2008 Pew Research Center study estimates that 10.1% of people in the United States describe themselves as former Catholics in some sense. In total the study reports that 44% of Americans profess a different religious affiliation than the one they were raised in. A majority converted to another religion while a substantial minority are counted as currently unaffiliated.
Note: The list includes those who leave the Catholic Church including any Eastern Catholic Church which is in communion with it. People such as Eddie Doherty, who were allowed to transfer from the Latin Catholic Church to an Eastern Catholic church, or vice versa are not considered as "former Roman Catholics", while Eastern Catholics who convert to a non-Catholic church or another religion are considered as such, even though Eastern Catholics do not typically refer to themselves as "Roman".
Individuals who converted to other churches, denominations and faiths
Eastern Orthodoxy
Rod Dreher, writer who converted to Catholicism and then to Eastern Orthodoxy
H. Tristram Engelhardt Jr., philosopher and bioethicist
Tom Hanks, actor, was involved with Catholicism, Mormonism and the Nazarens as a child, and was a "Bible-toting evangelical teenager", and converted to the Greek Orthodox Church after marrying his second wife. Karl Matzek, artist who joined the Eastern Orthodox Church John Anthony McGuckin, scholar, poet, and priest of the Romanian Orthodox Church Alexis Toth, Ruthenian Catholic Church priest who converted to Orthodoxy and became a saint in the Orthodox Church in America Nathaniel (Popp), archbishop of the Orthodox Church in America's Romanian Episcopate and former interim Metropolitan of the Orthodox Church in America who converted from the Romanian Greek-Catholic Church on 15 February 1968 Helen of Anjou, queen consort of the Serbian Kingdom Ita Rina, Yugoslav film actress and beauty queen