Did the Catholic Church add books to the Bible, or did Protestants remove them?

Neither framing is quite fair, and the real story is older and more interesting than either accusation.

Jewish tradition by the first century generally recognized a set of Hebrew scriptures matching what Protestant Old Testaments contain today. But many early Christians, especially Greek-speaking ones, also used a wider collection of Jewish writings—like Tobit, Judith, Wisdom, and 1–2 Maccabees—found in a Greek translation called the Septuagint. Early church leaders genuinely disagreed about their status; a scholar named Jerome favored the shorter Hebrew list, while another influential leader, Augustine, favored including the wider Greek collection.

For centuries, both were used with varying levels of authority across different regions. The split hardened at the Reformation: Protestant reformers followed the Hebrew canon, as Jerome had centuries earlier, while the Catholic Church formally defined its wider Old Testament, including those extra books, at the Council of Trent in 1546.

So it isn't quite accurate to say Catholics "added" or Protestants "removed" anything. Both traditions trace their position to a genuine, centuries-old disagreement about which ancient Jewish collection to follow—a real difference between Christian traditions that still stands today, held respectfully by both sides.