diff --git a/app/main.py b/app/main.py
index 32ec79a..9a9a88a 100644
--- a/app/main.py
+++ b/app/main.py
@@ -132,6 +132,19 @@ def list_issues(
     return issues
 
 
+@app.get("/issues/overdue", response_model=List[schemas.IssueResponse])
+def list_overdue_issues(project_id: int = None, db: Session = Depends(get_db)):
+    """List issues past their due date that aren't closed/resolved."""
+    query = db.query(models.Issue).filter(
+        models.Issue.due_date != None,
+        models.Issue.due_date < datetime.utcnow(),
+        models.Issue.status.notin_(["resolved", "closed"])
+    )
+    if project_id:
+        query = query.filter(models.Issue.project_id == project_id)
+    return query.order_by(models.Issue.due_date.asc()).all()
+
+
 @app.get("/issues/{issue_id}", response_model=schemas.IssueResponse)
 def get_issue(issue_id: int, db: Session = Depends(get_db)):
     issue = db.query(models.Issue).filter(models.Issue.id == issue_id).first()
@@ -254,6 +267,7 @@ def startup():
     from app.models import webhook
     from app.models import apikey
     from app.models import activity
+    from app.models import milestone
     Base.metadata.create_all(bind=engine)
 
 
@@ -772,3 +786,117 @@ def list_all_tags(project_id: int = None, db: Session = Depends(get_db)):
             if t:
                 all_tags.add(t)
     return {"tags": sorted(all_tags)}
+
+
+# ============ Milestones API ============
+
+from app.models.milestone import Milestone as MilestoneModel, MilestoneStatus
+from app.schemas.schemas import MilestoneCreate, MilestoneUpdate, MilestoneResponse
+
+
+@app.post("/milestones", response_model=MilestoneResponse, status_code=status.HTTP_201_CREATED)
+def create_milestone(ms: MilestoneCreate, db: Session = Depends(get_db)):
+    db_ms = MilestoneModel(**ms.model_dump())
+    db.add(db_ms)
+    db.commit()
+    db.refresh(db_ms)
+    return db_ms
+
+
+@app.get("/milestones", response_model=List[MilestoneResponse])
+def list_milestones(project_id: int = None, status_filter: str = None, db: Session = Depends(get_db)):
+    query = db.query(MilestoneModel)
+    if project_id:
+        query = query.filter(MilestoneModel.project_id == project_id)
+    if status_filter:
+        query = query.filter(MilestoneModel.status == status_filter)
+    return query.order_by(MilestoneModel.due_date.is_(None), MilestoneModel.due_date.asc()).all()
+
+
+@app.get("/milestones/{milestone_id}", response_model=MilestoneResponse)
+def get_milestone(milestone_id: int, db: Session = Depends(get_db)):
+    ms = db.query(MilestoneModel).filter(MilestoneModel.id == milestone_id).first()
+    if not ms:
+        raise HTTPException(status_code=404, detail="Milestone not found")
+    return ms
+
+
+@app.patch("/milestones/{milestone_id}", response_model=MilestoneResponse)
+def update_milestone(milestone_id: int, ms_update: MilestoneUpdate, db: Session = Depends(get_db)):
+    ms = db.query(MilestoneModel).filter(MilestoneModel.id == milestone_id).first()
+    if not ms:
+        raise HTTPException(status_code=404, detail="Milestone not found")
+    for field, value in ms_update.model_dump(exclude_unset=True).items():
+        setattr(ms, field, value)
+    db.commit()
+    db.refresh(ms)
+    return ms
+
+
+@app.delete("/milestones/{milestone_id}", status_code=status.HTTP_204_NO_CONTENT)
+def delete_milestone(milestone_id: int, db: Session = Depends(get_db)):
+    ms = db.query(MilestoneModel).filter(MilestoneModel.id == milestone_id).first()
+    if not ms:
+        raise HTTPException(status_code=404, detail="Milestone not found")
+    db.delete(ms)
+    db.commit()
+    return None
+
+
+@app.get("/milestones/{milestone_id}/issues", response_model=List[schemas.IssueResponse])
+def list_milestone_issues(milestone_id: int, db: Session = Depends(get_db)):
+    """List all issues in a milestone."""
+    return db.query(models.Issue).filter(models.Issue.milestone_id == milestone_id).all()
+
+
+@app.get("/milestones/{milestone_id}/progress")
+def milestone_progress(milestone_id: int, db: Session = Depends(get_db)):
+    """Get milestone completion progress."""
+    ms = db.query(MilestoneModel).filter(MilestoneModel.id == milestone_id).first()
+    if not ms:
+        raise HTTPException(status_code=404, detail="Milestone not found")
+    issues = db.query(models.Issue).filter(models.Issue.milestone_id == milestone_id).all()
+    total = len(issues)
+    done = sum(1 for i in issues if i.status in ("resolved", "closed"))
+    return {
+        "milestone_id": milestone_id,
+        "title": ms.title,
+        "total_issues": total,
+        "completed": done,
+        "progress_pct": round(done / total * 100, 1) if total else 0,
+    }
+
+
+# ============ Export API ============
+
+import csv
+import io
+from fastapi.responses import StreamingResponse
+
+
+@app.get("/export/issues")
+def export_issues_csv(project_id: int = None, db: Session = Depends(get_db)):
+    """Export issues as CSV."""
+    query = db.query(models.Issue)
+    if project_id:
+        query = query.filter(models.Issue.project_id == project_id)
+    issues = query.all()
+
+    output = io.StringIO()
+    writer = csv.writer(output)
+    writer.writerow(["id", "title", "type", "status", "priority", "project_id",
+                      "reporter_id", "assignee_id", "milestone_id", "due_date",
+                      "tags", "created_at", "updated_at"])
+    for i in issues:
+        writer.writerow([
+            i.id, i.title, i.issue_type, i.status, i.priority,
+            i.project_id, i.reporter_id, i.assignee_id, i.milestone_id,
+            i.due_date, i.tags, i.created_at, i.updated_at
+        ])
+    output.seek(0)
+    return StreamingResponse(
+        iter([output.getvalue()]),
+        media_type="text/csv",
+        headers={"Content-Disposition": "attachment; filename=issues.csv"}
+    )
+
diff --git a/app/models/milestone.py b/app/models/milestone.py
new file mode 100644
index 0000000..8758435
--- /dev/null
+++ b/app/models/milestone.py
@@ -0,0 +1,25 @@
+from sqlalchemy import Column, Integer, String, Text, DateTime, ForeignKey, Enum
+from sqlalchemy.orm import relationship
+from sqlalchemy.sql import func
+from app.core.config import Base
+import enum
+
+
+class MilestoneStatus(str, enum.Enum):
+    OPEN = "open"
+    CLOSED = "closed"
+
+
+class Milestone(Base):
+    __tablename__ = "milestones"
+
+    id = Column(Integer, primary_key=True, index=True)
+    title = Column(String(255), nullable=False)
+    description = Column(Text, nullable=True)
+    status = Column(Enum(MilestoneStatus), default=MilestoneStatus.OPEN)
+    due_date = Column(DateTime(timezone=True), nullable=True)
+    project_id = Column(Integer, ForeignKey("projects.id"), nullable=False)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), onupdate=func.now())
+
+    project = relationship("Project")
diff --git a/app/models/models.py b/app/models/models.py
index 6475e97..207d316 100644
--- a/app/models/models.py
+++ b/app/models/models.py
@@ -56,6 +56,10 @@ class Issue(Base):
     # Dependencies
     depends_on_id = Column(Integer, ForeignKey("issues.id"), nullable=True)
     
+    # Due date and milestone
+    due_date = Column(DateTime(timezone=True), nullable=True)
+    milestone_id = Column(Integer, ForeignKey("milestones.id"), nullable=True)
+    
     project = relationship("Project", back_populates="issues")
     reporter = relationship("User", foreign_keys=[reporter_id], back_populates="reported_issues")
     assignee = relationship("User", foreign_keys=[assignee_id], back_populates="assigned_issues")
diff --git a/app/schemas/schemas.py b/app/schemas/schemas.py
index 956a67b..88bbf2f 100644
--- a/app/schemas/schemas.py
+++ b/app/schemas/schemas.py
@@ -34,6 +34,8 @@ class IssueBase(BaseModel):
     priority: IssuePriorityEnum = IssuePriorityEnum.MEDIUM
     tags: Optional[str] = None
     depends_on_id: Optional[int] = None
+    due_date: Optional[datetime] = None
+    milestone_id: Optional[int] = None
 
 
 class IssueCreate(IssueBase):
@@ -54,6 +56,8 @@ class IssueUpdate(BaseModel):
     assignee_id: Optional[int] = None
     tags: Optional[str] = None
     depends_on_id: Optional[int] = None
+    due_date: Optional[datetime] = None
+    milestone_id: Optional[int] = None
     # Resolution specific
     resolution_summary: Optional[str] = None
     positions: Optional[str] = None
@@ -69,6 +73,8 @@ class IssueResponse(IssueBase):
     resolution_summary: Optional[str]
     positions: Optional[str]
     pending_matters: Optional[str]
+    due_date: Optional[datetime] = None
+    milestone_id: Optional[int] = None
     created_at: datetime
     updated_at: Optional[datetime]
     
@@ -163,3 +169,32 @@ class ProjectMemberResponse(ProjectMemberBase):
     
     class Config:
         from_attributes = True
+
+
+# Milestone schemas
+class MilestoneBase(BaseModel):
+    title: str
+    description: Optional[str] = None
+    due_date: Optional[datetime] = None
+
+
+class MilestoneCreate(MilestoneBase):
+    project_id: int
+
+
+class MilestoneUpdate(BaseModel):
+    title: Optional[str] = None
+    description: Optional[str] = None
+    status: Optional[str] = None
+    due_date: Optional[datetime] = None
+
+
+class MilestoneResponse(MilestoneBase):
+    id: int
+    status: str
+    project_id: int
+    created_at: datetime
+    updated_at: Optional[datetime] = None
+
+    class Config:
+        from_attributes = True