Recent high-profile cases and harrowing testimony given to public inquiries have kept the issue in the headlines.
Meanwhile alleged cover-ups continue to dog the Church, and victims groups say the Vatican has not done nearly enough to right its wrongs.
Here's what you need to know.
How did this all come to light?
Although some accusations date back to the 1950s, molestation by priests was first given significant media attention in the 1980s, in the US and Canada.
In the 1990s the issue began to grow, with stories emerging in Argentina, Australia and elsewhere. In 1995, the Archbishop of Vienna, Austria, stepped down amid sexual abuse allegations, rocking the Church there.
Also in that decade, revelations began of widespread historical abuse in Ireland. By the early 2000s, Church sexual abuse was a major global story.
In the US, determined reporting by the Boston Globe newspaper (as captured in the 2015 film Spotlight) exposed widespread abuse and how paedophile priests were moved around by Church leaders instead of being held accountable. It prompted people to come forward across the US and around the world.
A Church-commissioned report in 2004 said more than 4,000 US Roman Catholic priests had faced sexual abuse allegations in the last 50 years, in cases involving more than 10,000 children - mostly boys.
A 2009 report found that sexual and psychological abuse was "endemic" in Catholic-run industrial schools and orphanages in Ireland for most of the 20th Century.
World Catholic sex abuse scandals
UN: Vatican must remove abusers
A five-year Australian inquiry in 2017 found that "tens of thousands of children" were sexually abused in Australian institutions over decades, including churches, schools and sports clubs.