diff --git a/app/models/base.py b/app/models/base.py
new file mode 100644
index 0000000..dd6656b
--- /dev/null
+++ b/app/models/base.py
@@ -0,0 +1,52 @@
+"""Base model and reusable mixins for the CRM system."""
+
+from __future__ import annotations
+
+from datetime import datetime
+from typing import Optional
+
+from sqlalchemy import DateTime, ForeignKey, func
+from sqlalchemy.orm import Mapped, mapped_column
+
+from app.core.db import Base
+
+
+class TimestampMixin:
+    """Adds created_at and updated_at columns to a model."""
+
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
+        server_default=func.now(),
+        nullable=False,
+        index=True,
+    )
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
+        server_default=func.now(),
+        onupdate=func.now(),
+        nullable=False,
+    )
+
+
+class SoftDeleteMixin:
+    """Adds deleted_at column for soft-delete pattern."""
+
+    deleted_at: Mapped[Optional[datetime]] = mapped_column(
+        DateTime(timezone=True),
+        nullable=True,
+        default=None,
+        index=True,
+    )
+
+
+class OrgScopedMixin:
+    """Adds org_id foreign key. All queries must filter by org_id (OrgScopedQuery)."""
+
+    org_id: Mapped[int] = mapped_column(
+        ForeignKey("orgs.id", ondelete="CASCADE"),
+        nullable=False,
+        index=True,
+    )
+
+
+__all__ = ["Base", "OrgScopedMixin", "SoftDeleteMixin", "TimestampMixin"]