diff --git a/alembic/versions/006_name_manually_edited.py b/alembic/versions/006_name_manually_edited.py
new file mode 100644
index 0000000..62bb076
--- /dev/null
+++ b/alembic/versions/006_name_manually_edited.py
@@ -0,0 +1,35 @@
+"""Add name_manually_edited to users
+
+Revision ID: 006
+Revises: 005
+Create Date: 2025-02-19
+
+When True, full_name/first_name/last_name are not overwritten by get_or_create_user
+(Telegram sync). Set manually or via update_user_display_name when editing name in DB/API.
+"""
+
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+revision: str = "006"
+down_revision: Union[str, None] = "005"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.add_column(
+        "users",
+        sa.Column(
+            "name_manually_edited",
+            sa.Boolean(),
+            nullable=False,
+            server_default=sa.text("0"),
+        ),
+    )
+
+
+def downgrade() -> None:
+    op.drop_column("users", "name_manually_edited")
diff --git a/duty_teller/db/__init__.py b/duty_teller/db/__init__.py
index 60127ce..7e3a2f2 100644
--- a/duty_teller/db/__init__.py
+++ b/duty_teller/db/__init__.py
@@ -21,6 +21,7 @@ from duty_teller.db.repository import (
     get_duties,
     insert_duty,
     set_user_phone,
+    update_user_display_name,
 )
 
 __all__ = [
@@ -42,6 +43,7 @@ __all__ = [
     "get_duties",
     "insert_duty",
     "set_user_phone",
+    "update_user_display_name",
     "init_db",
 ]
 
diff --git a/duty_teller/db/models.py b/duty_teller/db/models.py
index 51bccca..6265e1e 100644
--- a/duty_teller/db/models.py
+++ b/duty_teller/db/models.py
@@ -1,6 +1,6 @@
 """SQLAlchemy ORM models for users and duties."""
 
-from sqlalchemy import ForeignKey, Integer, BigInteger, Text
+from sqlalchemy import Boolean, ForeignKey, Integer, BigInteger, Text
 from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column, relationship
 
 
@@ -22,6 +22,9 @@ class User(Base):
     first_name: Mapped[str | None] = mapped_column(Text, nullable=True)
     last_name: Mapped[str | None] = mapped_column(Text, nullable=True)
     phone: Mapped[str | None] = mapped_column(Text, nullable=True)
+    name_manually_edited: Mapped[bool] = mapped_column(
+        Boolean, nullable=False, server_default="0", default=False
+    )
 
     duties: Mapped[list["Duty"]] = relationship("Duty", back_populates="user")
 
diff --git a/duty_teller/db/repository.py b/duty_teller/db/repository.py
index 4196404..9ff2cb5 100644
--- a/duty_teller/db/repository.py
+++ b/duty_teller/db/repository.py
@@ -23,12 +23,18 @@ def get_or_create_user(
     first_name: str | None = None,
     last_name: str | None = None,
 ) -> User:
+    """
+    Get or create user by telegram_user_id. On create, name comes from Telegram.
+    On update: username is always synced; full_name/first_name/last_name are only
+    updated if name_manually_edited is False (otherwise keep existing display name).
+    """
     user = get_user_by_telegram_id(session, telegram_user_id)
     if user:
-        user.full_name = full_name
         user.username = username
-        user.first_name = first_name
-        user.last_name = last_name
+        if not user.name_manually_edited:
+            user.full_name = full_name
+            user.first_name = first_name
+            user.last_name = last_name
         session.commit()
         session.refresh(user)
         return user
@@ -38,6 +44,7 @@ def get_or_create_user(
         username=username,
         first_name=first_name,
         last_name=last_name,
+        name_manually_edited=False,
     )
     session.add(user)
     session.commit()
@@ -46,7 +53,10 @@ def get_or_create_user(
 
 
 def get_or_create_user_by_full_name(session: Session, full_name: str) -> User:
-    """Find user by exact full_name or create one with telegram_user_id=None (for duty-schedule import)."""
+    """
+    Find user by exact full_name or create one with telegram_user_id=None (for duty-schedule import).
+    New users get name_manually_edited=True since the name comes from import, not Telegram.
+    """
     user = session.query(User).filter(User.full_name == full_name).first()
     if user:
         return user
@@ -56,6 +66,7 @@ def get_or_create_user_by_full_name(session: Session, full_name: str) -> User:
         username=None,
         first_name=None,
         last_name=None,
+        name_manually_edited=True,
     )
     session.add(user)
     session.commit()
@@ -63,6 +74,30 @@ def get_or_create_user_by_full_name(session: Session, full_name: str) -> User:
     return user
 
 
+def update_user_display_name(
+    session: Session,
+    telegram_user_id: int,
+    full_name: str,
+    first_name: str | None = None,
+    last_name: str | None = None,
+) -> User | None:
+    """
+    Update display name for user by telegram_user_id and set name_manually_edited=True.
+    Use from API or admin when name is changed manually; subsequent get_or_create_user
+    will not overwrite these fields. Returns User or None if not found.
+    """
+    user = session.query(User).filter(User.telegram_user_id == telegram_user_id).first()
+    if not user:
+        return None
+    user.full_name = full_name
+    user.first_name = first_name
+    user.last_name = last_name
+    user.name_manually_edited = True
+    session.commit()
+    session.refresh(user)
+    return user
+
+
 def delete_duties_in_range(
     session: Session,
     user_id: int,
diff --git a/tests/test_repository_duty_range.py b/tests/test_repository_duty_range.py
index 2090328..c655997 100644
--- a/tests/test_repository_duty_range.py
+++ b/tests/test_repository_duty_range.py
@@ -1,4 +1,4 @@
-"""Tests for delete_duties_in_range and get_or_create_user_by_full_name."""
+"""Tests for delete_duties_in_range, get_or_create_user_by_full_name, name_manually_edited."""
 
 import pytest
 from sqlalchemy import create_engine
@@ -7,9 +7,11 @@ from sqlalchemy.orm import sessionmaker
 from duty_teller.db.models import Base, User
 from duty_teller.db.repository import (
     delete_duties_in_range,
+    get_or_create_user,
     get_or_create_user_by_full_name,
     get_duties,
     insert_duty,
+    update_user_display_name,
 )
 
 
@@ -47,6 +49,7 @@ def test_get_or_create_user_by_full_name_creates(session):
     assert u.id is not None
     assert u.full_name == "Новый Пользователь"
     assert u.telegram_user_id is None
+    assert u.name_manually_edited is True
 
 
 def test_get_or_create_user_by_full_name_returns_existing(session, user_a):
@@ -107,3 +110,88 @@ def test_get_duties_includes_duty_starting_on_last_day_of_range(session, user_a)
     assert len(rows) == 1
     assert rows[0][0].start_at == "2026-01-31T09:00:00Z"
     assert rows[0][1] == "User A"
+
+
+def test_get_or_create_user_overwrites_name_when_flag_false(session):
+    """When name_manually_edited is False, second get_or_create_user overwrites name."""
+    u1 = get_or_create_user(
+        session,
+        telegram_user_id=100,
+        full_name="First Name",
+        username="user1",
+        first_name="First",
+        last_name="Name",
+    )
+    assert u1.full_name == "First Name"
+    assert u1.name_manually_edited is False
+    u2 = get_or_create_user(
+        session,
+        telegram_user_id=100,
+        full_name="Second Name",
+        username="user2",
+        first_name="Second",
+        last_name="Name",
+    )
+    assert u2.id == u1.id
+    assert u2.full_name == "Second Name"
+    assert u2.first_name == "Second"
+    assert u2.last_name == "Name"
+    assert u2.username == "user2"
+
+
+def test_get_or_create_user_keeps_name_when_flag_true_updates_username(session):
+    """When name_manually_edited is True, get_or_create_user keeps name but updates username."""
+    u1 = get_or_create_user(
+        session,
+        telegram_user_id=200,
+        full_name="Custom Name",
+        username="old_username",
+        first_name="Custom",
+        last_name="Name",
+    )
+    u1.name_manually_edited = True
+    session.commit()
+    session.refresh(u1)
+    u2 = get_or_create_user(
+        session,
+        telegram_user_id=200,
+        full_name="Telegram Name",
+        username="new_username",
+        first_name="Telegram",
+        last_name="Name",
+    )
+    assert u2.id == u1.id
+    assert u2.full_name == "Custom Name"
+    assert u2.first_name == "Custom"
+    assert u2.last_name == "Name"
+    assert u2.username == "new_username"
+
+
+def test_update_user_display_name_sets_flag_then_get_or_create_user_keeps_name(session):
+    """update_user_display_name sets name and flag; get_or_create_user then does not overwrite name."""
+    get_or_create_user(
+        session,
+        telegram_user_id=300,
+        full_name="Original",
+        username="u3",
+        first_name="Original",
+        last_name=None,
+    )
+    updated = update_user_display_name(
+        session, 300, "Manual Name", first_name="Manual", last_name="Name"
+    )
+    assert updated is not None
+    assert updated.full_name == "Manual Name"
+    assert updated.name_manually_edited is True
+    u_after_sync = get_or_create_user(
+        session,
+        telegram_user_id=300,
+        full_name="From Telegram",
+        username="new_u3",
+        first_name="From",
+        last_name="Telegram",
+    )
+    assert u_after_sync.full_name == "Manual Name"
+    assert u_after_sync.first_name == "Manual"
+    assert u_after_sync.last_name == "Name"
+    assert u_after_sync.username == "new_u3"