The exact phrase “separation of church and state” does not appear in the U.S. Constitution. The idea comes mainly from the First Amendment, especially the part that says, “Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof.”

Where it comes from

  • First Amendment, Establishment Clause : stops the government from creating an official religion or favoring one religion over another.
  • First Amendment, Free Exercise Clause : protects people’s right to practice religion freely.
  • The famous “wall of separation” wording is associated with Thomas Jefferson’s later letter, not the Constitution itself.

Simple takeaway

So if someone asks, “Where in the Constitution is separation of church and state?” the best answer is: it’s not written as that exact phrase anywhere; it’s inferred from the First Amendment’s religion clauses.

TL;DR

The phrase itself is not in the Constitution, but the principle is usually traced to the First Amendment’s ban on establishing religion and its protection of free exercise.