diff --git a/CHANGELOG.md b/CHANGELOG.md
index 567347c2..58dbc993 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@ and this project adheres to
 
 - Implement `OperationalUnit` schema
 - Link `OperationalUnit` to `Station` using AFIREV prefixes
+- Implement `User` and `Group` schemas
 
 ## [0.5.0] - 2024-05-15
 
diff --git a/src/api/qualicharge/auth/factories.py b/src/api/qualicharge/auth/factories.py
index d2047444..067ed859 100644
--- a/src/api/qualicharge/auth/factories.py
+++ b/src/api/qualicharge/auth/factories.py
@@ -4,13 +4,15 @@
 from datetime import datetime
 from typing import Any, Dict
 
-from polyfactory import PostGenerated
+from polyfactory import PostGenerated, Use
 from polyfactory.factories.pydantic_factory import ModelFactory
 from polyfactory.pytest_plugin import register_fixture
 
 from qualicharge.conf import settings
+from qualicharge.factories import FrenchDataclassFactory, TimestampedSQLModelFactory
 
 from .models import IDToken
+from .schemas import Group, User
 
 
 def set_token_exp(name: str, values: Dict[str, int], *args: Any, **kwargs: Any) -> int:
@@ -29,3 +31,20 @@ class IDTokenFactory(ModelFactory[IDToken]):
     iat = int(datetime.now().timestamp())
     scope = "email profile"
     email = "john@doe.com"
+
+
+class UserFactory(TimestampedSQLModelFactory[User]):
+    """User schema factory."""
+
+    username = Use(
+        lambda: FrenchDataclassFactory.__faker__.simple_profile().get("username")
+    )
+    email = Use(FrenchDataclassFactory.__faker__.ascii_company_email)
+    first_name = Use(FrenchDataclassFactory.__faker__.first_name)
+    last_name = Use(FrenchDataclassFactory.__faker__.last_name)
+
+
+class GroupFactory(TimestampedSQLModelFactory[Group]):
+    """Group schema factory."""
+
+    name = Use(FrenchDataclassFactory.__faker__.company)
diff --git a/src/api/qualicharge/auth/schemas.py b/src/api/qualicharge/auth/schemas.py
new file mode 100644
index 00000000..629e6fbd
--- /dev/null
+++ b/src/api/qualicharge/auth/schemas.py
@@ -0,0 +1,60 @@
+"""QualiCharge authentication schemas."""
+
+from typing import TYPE_CHECKING, Optional
+from uuid import UUID, uuid4
+
+from pydantic import EmailStr
+from sqlalchemy.types import String
+from sqlmodel import Field, Relationship, SQLModel
+
+from qualicharge.schemas import BaseTimestampedSQLModel
+
+if TYPE_CHECKING:
+    from qualicharge.schemas.core import OperationalUnit
+
+
+# -- Many-to-many relationships
+class UserGroup(SQLModel, table=True):
+    """M2M User-Group intermediate table."""
+
+    user_id: UUID = Field(foreign_key="user.id", primary_key=True)
+    group_id: UUID = Field(foreign_key="group.id", primary_key=True)
+
+
+class GroupOperationalUnit(SQLModel, table=True):
+    """M2M Group-OperationalUnit intermediate table."""
+
+    group_id: UUID = Field(foreign_key="group.id", primary_key=True)
+    operational_unit_id: UUID = Field(
+        foreign_key="operationalunit.id", primary_key=True
+    )
+
+
+# -- Core schemas
+class User(BaseTimestampedSQLModel, table=True):
+    """QualiCharge User."""
+
+    id: Optional[UUID] = Field(default_factory=lambda: uuid4().hex, primary_key=True)
+    username: str = Field(unique=True, max_length=150)
+    email: EmailStr = Field(sa_type=String)
+    first_name: Optional[str] = Field(max_length=150)
+    last_name: Optional[str] = Field(max_length=150)
+    is_active: bool = False
+    is_staff: bool = False
+    is_superuser: bool = False
+
+    # Relationships
+    groups: list["Group"] = Relationship(back_populates="users", link_model=UserGroup)
+
+
+class Group(BaseTimestampedSQLModel, table=True):
+    """QualiCharge Group."""
+
+    id: Optional[UUID] = Field(default_factory=lambda: uuid4().hex, primary_key=True)
+    name: str = Field(unique=True, max_length=150)
+
+    # Relationships
+    users: list["User"] = Relationship(back_populates="groups", link_model=UserGroup)
+    operational_units: list["OperationalUnit"] = Relationship(
+        back_populates="groups", link_model=GroupOperationalUnit
+    )
diff --git a/src/api/qualicharge/auth/utils.py b/src/api/qualicharge/auth/utils.py
new file mode 100644
index 00000000..8f6296bf
--- /dev/null
+++ b/src/api/qualicharge/auth/utils.py
@@ -0,0 +1,21 @@
+"""QualiCharge auth.utils module."""
+
+from typing import Sequence, cast
+
+from sqlalchemy import Column as SAColumn
+from sqlalchemy.sql.roles import JoinTargetRole
+from sqlmodel import Session as SMSession
+from sqlmodel import select
+
+from qualicharge.schemas.core import OperationalUnit
+
+from .schemas import Group, User
+
+
+def get_user_operational_units(user: User, session: SMSession) -> Sequence[str]:
+    """Get user related operational unit codes."""
+    return session.exec(
+        select(OperationalUnit.code)
+        .join(cast(JoinTargetRole, OperationalUnit.groups))
+        .filter(cast(SAColumn, Group.id).in_(group.id for group in user.groups))
+    ).all()
diff --git a/src/api/qualicharge/migrations/env.py b/src/api/qualicharge/migrations/env.py
index f282ebb0..35c54abc 100644
--- a/src/api/qualicharge/migrations/env.py
+++ b/src/api/qualicharge/migrations/env.py
@@ -9,6 +9,12 @@
 from qualicharge.conf import settings
 
 # Nota bene: be sure to import all models that need to be migrated here
+from qualicharge.auth.schemas import (  # noqa: F401
+    User,
+    UserGroup,
+    Group,
+    GroupOperationalUnit,
+)
 from qualicharge.schemas.core import (  # noqa: F401
     Amenageur,
     Enseigne,
diff --git a/src/api/qualicharge/migrations/versions/7568f5ff860e_add_user_and_group_schemas.py b/src/api/qualicharge/migrations/versions/7568f5ff860e_add_user_and_group_schemas.py
new file mode 100644
index 00000000..b98ec9c5
--- /dev/null
+++ b/src/api/qualicharge/migrations/versions/7568f5ff860e_add_user_and_group_schemas.py
@@ -0,0 +1,88 @@
+"""add user and group schemas
+
+Revision ID: 7568f5ff860e
+Revises: fda96abb970d
+Create Date: 2024-05-20 14:20:28.454872
+
+"""
+
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+import sqlmodel
+from sqlalchemy.dialects import postgresql
+
+# revision identifiers, used by Alembic.
+revision: str = "7568f5ff860e"
+down_revision: Union[str, None] = "fda96abb970d"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_table(
+        "group",
+        sa.Column("created_at", sa.DateTime(timezone=True), nullable=False),
+        sa.Column("updated_at", sa.DateTime(timezone=True), nullable=False),
+        sa.Column("id", sqlmodel.sql.sqltypes.GUID(), nullable=False),
+        sa.Column("name", sqlmodel.sql.sqltypes.AutoString(), nullable=False),
+        sa.CheckConstraint("created_at <= updated_at", name="pre-creation-update"),
+        sa.PrimaryKeyConstraint("id"),
+        sa.UniqueConstraint("name"),
+    )
+    op.create_table(
+        "user",
+        sa.Column("created_at", sa.DateTime(timezone=True), nullable=False),
+        sa.Column("updated_at", sa.DateTime(timezone=True), nullable=False),
+        sa.Column("id", sqlmodel.sql.sqltypes.GUID(), nullable=False),
+        sa.Column("username", sqlmodel.sql.sqltypes.AutoString(), nullable=False),
+        sa.Column("email", sa.String(), nullable=False),
+        sa.Column("first_name", sqlmodel.sql.sqltypes.AutoString(), nullable=True),
+        sa.Column("last_name", sqlmodel.sql.sqltypes.AutoString(), nullable=True),
+        sa.Column("is_active", sa.Boolean(), nullable=False),
+        sa.Column("is_staff", sa.Boolean(), nullable=False),
+        sa.Column("is_superuser", sa.Boolean(), nullable=False),
+        sa.CheckConstraint("created_at <= updated_at", name="pre-creation-update"),
+        sa.PrimaryKeyConstraint("id"),
+        sa.UniqueConstraint("username"),
+    )
+    op.create_table(
+        "groupoperationalunit",
+        sa.Column("group_id", sqlmodel.sql.sqltypes.GUID(), nullable=False),
+        sa.Column("operational_unit_id", sqlmodel.sql.sqltypes.GUID(), nullable=False),
+        sa.ForeignKeyConstraint(
+            ["group_id"],
+            ["group.id"],
+        ),
+        sa.ForeignKeyConstraint(
+            ["operational_unit_id"],
+            ["operationalunit.id"],
+        ),
+        sa.PrimaryKeyConstraint("group_id", "operational_unit_id"),
+    )
+    op.create_table(
+        "usergroup",
+        sa.Column("user_id", sqlmodel.sql.sqltypes.GUID(), nullable=False),
+        sa.Column("group_id", sqlmodel.sql.sqltypes.GUID(), nullable=False),
+        sa.ForeignKeyConstraint(
+            ["group_id"],
+            ["group.id"],
+        ),
+        sa.ForeignKeyConstraint(
+            ["user_id"],
+            ["user.id"],
+        ),
+        sa.PrimaryKeyConstraint("user_id", "group_id"),
+    )
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_table("usergroup")
+    op.drop_table("groupoperationalunit")
+    op.drop_table("user")
+    op.drop_table("group")
+    # ### end Alembic commands ###
diff --git a/src/api/qualicharge/schemas/core.py b/src/api/qualicharge/schemas/core.py
index 26b8576c..0b1a046f 100644
--- a/src/api/qualicharge/schemas/core.py
+++ b/src/api/qualicharge/schemas/core.py
@@ -26,6 +26,7 @@
 from sqlmodel import Session as SMSession
 from sqlmodel.main import SQLModelConfig
 
+from qualicharge.auth.schemas import Group, GroupOperationalUnit
 from qualicharge.exceptions import ObjectDoesNotExist
 
 from ..models.dynamic import SessionBase, StatusBase
@@ -187,7 +188,11 @@ class OperationalUnit(BaseTimestampedSQLModel, table=True):
     name: str
     type: OperationalUnitTypeEnum
 
+    # Relationships
     stations: List["Station"] = Relationship(back_populates="operational_unit")
+    groups: List["Group"] = Relationship(
+        back_populates="operational_units", link_model=GroupOperationalUnit
+    )
 
     def create_stations_fk(self, session: SMSession):
         """Create linked stations foreign keys."""
diff --git a/src/api/tests/auth/__init__.py b/src/api/tests/auth/__init__.py
new file mode 100644
index 00000000..e1441c22
--- /dev/null
+++ b/src/api/tests/auth/__init__.py
@@ -0,0 +1 @@
+"""QualiCharge auth module tests."""
diff --git a/src/api/tests/auth/test_schemas.py b/src/api/tests/auth/test_schemas.py
new file mode 100644
index 00000000..03de2fbe
--- /dev/null
+++ b/src/api/tests/auth/test_schemas.py
@@ -0,0 +1,39 @@
+"""Tests for qualicharge.auth.schemas module."""
+
+from sqlmodel import select
+
+from qualicharge.auth.factories import GroupFactory, UserFactory
+from qualicharge.auth.schemas import GroupOperationalUnit, UserGroup
+from qualicharge.schemas.core import OperationalUnit
+
+
+def test_create_user_group_operational_units(db_session):
+    """Test the user to operational unit relationship."""
+    UserFactory.__session__ = db_session
+    GroupFactory.__session__ = db_session
+
+    # Create users and groups
+    user_one, user_two = UserFactory.create_batch_sync(2)
+    group_one, group_two = GroupFactory.create_batch_sync(2)
+    db_session.add(UserGroup(user_id=user_one.id, group_id=group_one.id))
+    db_session.add(UserGroup(user_id=user_two.id, group_id=group_two.id))
+
+    assert group_one.users == [
+        user_one,
+    ]
+    assert group_two.users == [
+        user_two,
+    ]
+
+    # Link group to an operational unit
+    code = "FRS63"
+    operational_unit = db_session.exec(
+        select(OperationalUnit).where(OperationalUnit.code == code)
+    ).one()
+    db_session.add(
+        GroupOperationalUnit(
+            group_id=group_one.id, operational_unit_id=operational_unit.id
+        )
+    )
+
+    assert user_one.groups[0].operational_units[0].id == operational_unit.id
diff --git a/src/api/tests/auth/test_utils.py b/src/api/tests/auth/test_utils.py
new file mode 100644
index 00000000..e3412e55
--- /dev/null
+++ b/src/api/tests/auth/test_utils.py
@@ -0,0 +1,51 @@
+"""Tests for qualicharge.auth.utils schemas module."""
+
+from random import sample
+from typing import cast
+
+from sqlalchemy import Column as SAColumn
+from sqlmodel import select
+
+from qualicharge.auth.factories import GroupFactory, UserFactory
+from qualicharge.auth.schemas import GroupOperationalUnit, UserGroup
+from qualicharge.auth.utils import get_user_operational_units
+from qualicharge.fixtures.operational_units import data as operational_unit_data
+from qualicharge.schemas.core import OperationalUnit
+
+
+def test_user_get_operational_units(db_session):
+    """Test the User get_operational_units utility."""
+    UserFactory.__session__ = db_session
+    GroupFactory.__session__ = db_session
+
+    # Create user, groups and link them (with operational units)
+    user = UserFactory.create_sync()
+    n_groups = 8
+    groups = GroupFactory.create_batch_sync(n_groups)
+    user_n_groups = 2
+    user_groups = sample(groups, user_n_groups)
+    operational_unit_codes = [
+        operational_unit.code
+        for operational_unit in sample(operational_unit_data, n_groups)
+    ]
+    operational_units = db_session.exec(
+        select(OperationalUnit).where(
+            cast(SAColumn, OperationalUnit.code).in_(operational_unit_codes)
+        )
+    )
+    db_session.add_all(
+        UserGroup(user_id=user.id, group_id=group.id) for group in user_groups
+    )
+    db_session.add_all(
+        GroupOperationalUnit(group_id=group.id, operational_unit_id=operational_unit.id)
+        for group, operational_unit in zip(groups, operational_units)
+    )
+
+    # Get operational unit codes
+    user_operational_unit_codes = get_user_operational_units(user, db_session)
+    assert len(user_operational_unit_codes) == user_n_groups
+    assert set(user_operational_unit_codes) == {
+        operational_unit.code
+        for group in user.groups
+        for operational_unit in group.operational_units
+    }