diff --git a/lib/galaxy/model/__init__.py b/lib/galaxy/model/__init__.py
index 8623aa442e90..8f7e0645c219 100644
--- a/lib/galaxy/model/__init__.py
+++ b/lib/galaxy/model/__init__.py
@@ -780,7 +780,7 @@ class User(Base, Dictifiable, RepresentById):
     id: Mapped[int] = mapped_column(primary_key=True)
     create_time: Mapped[datetime] = mapped_column(default=now, nullable=True)
     update_time: Mapped[datetime] = mapped_column(default=now, onupdate=now, nullable=True)
-    email: Mapped[str] = mapped_column(TrimmedString(255), index=True)
+    email: Mapped[str] = mapped_column(TrimmedString(255), index=True, unique=True)
     username: Mapped[Optional[str]] = mapped_column(TrimmedString(255), index=True, unique=True)
     password: Mapped[str] = mapped_column(TrimmedString(255))
     last_password_change: Mapped[Optional[datetime]] = mapped_column(default=now)