diff --git a/backend/alembic/versions/0003_add_groups_and_members.py b/backend/alembic/versions/0003_add_groups_and_members.py
new file mode 100644
index 0000000..43df8ce
--- /dev/null
+++ b/backend/alembic/versions/0003_add_groups_and_members.py
@@ -0,0 +1,52 @@
+"""add groups and group_members tables
+
+Revision ID: 0003_add_groups_and_members
+Revises: 0002_add_date_of_birth_to_users
+Create Date: 2025-01-01 00:00:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+# revision identifiers, used by Alembic.
+revision: str = "0003_add_groups_and_members"
+down_revision: Union[str, None] = "0002_add_date_of_birth_to_users"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Create groups and group_members tables."""
+    # Create groups table
+    op.create_table(
+        "groups",
+        sa.Column("id", sa.Integer(), primary_key=True, index=True),
+        sa.Column("name", sa.String(length=255), nullable=False),
+        sa.Column("description", sa.Text(), nullable=True),
+        sa.Column("owner_id", sa.Integer(), sa.ForeignKey("users.id", ondelete="CASCADE"), nullable=False),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now()),
+        sa.Column("updated_at", sa.DateTime(timezone=True), server_default=sa.func.now(), onupdate=sa.func.now()),
+    )
+
+    # Create group_members table
+    op.create_table(
+        "group_members",
+        sa.Column("group_id", sa.Integer(), sa.ForeignKey("groups.id", ondelete="CASCADE"), primary_key=True),
+        sa.Column("user_id", sa.Integer(), sa.ForeignKey("users.id", ondelete="CASCADE"), primary_key=True),
+        sa.Column(
+            "role",
+            postgresql.ENUM("owner", "admin", "member", name="group_member_role", create_type=False),
+            nullable=False,
+            default="member",
+        ),
+        sa.Column("joined_at", sa.DateTime(timezone=True), server_default=sa.func.now()),
+    )
+
+
+def downgrade() -> None:
+    """Drop group_members and groups tables."""
+    op.drop_table("group_members")
+    op.drop_table("groups")