diff --git a/app/models/account.py b/app/models/account.py
new file mode 100644
index 0000000..0e3315c
--- /dev/null
+++ b/app/models/account.py
@@ -0,0 +1,86 @@
+"""Account model: companies/organizations that the CRM tracks."""
+
+from __future__ import annotations
+
+from enum import Enum
+from typing import TYPE_CHECKING, Any, Optional
+
+from sqlalchemy import JSON, ForeignKey, String
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from app.models.base import Base, OrgScopedMixin, SoftDeleteMixin, TimestampMixin
+
+if TYPE_CHECKING:
+    from app.models.user import User
+    from app.models.contact import Contact
+    from app.models.deal import Deal
+    from app.models.activity import Activity
+    from app.models.note import Note
+    from app.models.tag_link import TagLink
+
+
+class Industry(str, Enum):
+    """Industry classification for accounts."""
+
+    startup = "startup"
+    sme = "sme"
+    midmarket = "midmarket"
+    enterprise = "enterprise"
+    other = "other"
+
+
+class AccountSize(str, Enum):
+    """Company size category."""
+
+    startup = "startup"
+    sme = "sme"
+    midmarket = "midmarket"
+    enterprise = "enterprise"
+
+
+class Account(Base, TimestampMixin, SoftDeleteMixin, OrgScopedMixin):
+    __tablename__ = "accounts"
+
+    id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)
+    name: Mapped[str] = mapped_column(String(255), nullable=False, index=True)
+    website: Mapped[Optional[str]] = mapped_column(String(512), nullable=True)
+    industry: Mapped[Optional[Industry]] = mapped_column(
+        String(32), nullable=True, index=True
+    )
+    size: Mapped[Optional[AccountSize]] = mapped_column(String(32), nullable=True)
+    address: Mapped[Optional[dict[str, Any]]] = mapped_column(JSON, nullable=True)
+    owner_id: Mapped[int] = mapped_column(
+        ForeignKey("users.id"), nullable=False, index=True
+    )
+
+    # Relationships
+    owner: Mapped["User"] = relationship(
+        "User", foreign_keys=[owner_id], lazy="joined"
+    )
+    contacts: Mapped[list["Contact"]] = relationship(
+        "Contact", back_populates="account", lazy="selectin"
+    )
+    deals: Mapped[list["Deal"]] = relationship(
+        "Deal", back_populates="account", lazy="selectin"
+    )
+    activities: Mapped[list["Activity"]] = relationship(
+        "Activity", back_populates="account", lazy="selectin"
+    )
+    notes: Mapped[list["Note"]] = relationship(
+        "Note",
+        primaryjoin="and_(Account.id==foreign(Note.parent_id), Note.parent_type=='account')",
+        viewonly=True,
+        lazy="selectin",
+    )
+    tags: Mapped[list["TagLink"]] = relationship(
+        "TagLink",
+        primaryjoin="and_(Account.id==foreign(TagLink.parent_id), TagLink.parent_type=='account')",
+        viewonly=True,
+        lazy="selectin",
+    )
+
+    def __repr__(self) -> str:
+        return f"<Account id={self.id} name={self.name!r}>"
+
+
+__all__ = ["Account", "AccountSize", "Industry"]