The phrase 'separation of church and state' is not explicitly stated in the U.S. Constitution because multiple reliable sources confirm that while the concept is derived from constitutional principles, the exact wording does not appear in the text.
Separation of Church and state is not in the Constitution.

Constitutional Expert On 'Separation Of Church And State': Framers Said Nothing Wrong With Religion In Culture - Media Coverage - Stanford Law School
Source: law.stanford.edu
Key Evidence
Stanford Law School confirms the phrase does not appear in the Constitution but notes framers accepted religion's role in culture.
law.stanford.edulaw.stanford.eduConstitutional Expert On 'Separation Of Church And State': Framers Said Nothing...
The Establishment Clause is often interpreted as requiring separation, though it does not use that phrase.
firstamendment.mtsu.edufirstamendment.mtsu.eduEstablishment Clause
Multiple educational and legal sources agree on the absence of the exact phrase while recognizing its conceptual influence.
bridgew.edubridgew.eduThe Doctrine of Separation of Church and State
constitutionus.comconstitutionus.comIs Separation of Church and State in the Constitution?+1 more
What the Evidence Shows
The phrase 'separation of church and state' does not appear anywhere in the U.S. Constitution. This is confirmed by several authoritative sources including Stanford Law School, Bridgewater State University, and constitutionus.com.law.stanford.edulaw.stanford.eduConstitutional Expert On 'Separation Of Church And State': Framers Said Nothing...
bridgew.edubridgew.eduThe Doctrine of Separation of Church and State+1 more The concept is often linked to the Establishment Clause of the First Amendment, which prohibits Congress from making laws respecting an establishment of religion, but the exact phrase itself was coined later and popularized through historical interpretation and legal commentary rather than constitutional text.
Thomas Jefferson famously used the phrase 'wall of separation between church and state' in an 1802 letter to the Danbury Baptist Association, which has influenced legal and cultural understandings but is not part of the Constitution itself.bsssb-llc.combsssb-llc.comThe Separation of Church and State Some sources, like Americans United, argue that separation is foundational to U.S. Government structure based on constitutional principles, but they acknowledge the phrase is not literally in the document.
au.orgau.orgIs the separation of church and state in the constitution
The absence of explicit mention does not mean there is no constitutional basis for separation; rather, it reflects that the phrase is a shorthand for judicial interpretations of clauses like the Establishment Clause. This distinction is important in legal debates and public discourse about religious freedom and government neutrality toward religion.