diff --git a/src/core/models.py b/src/core/models.py
new file mode 100644
index 0000000..7895ab3
--- /dev/null
+++ b/src/core/models.py
@@ -0,0 +1,133 @@
+"""Data models for scan results and issues."""
+
+from dataclasses import dataclass, field
+from datetime import datetime
+from enum import Enum
+from pathlib import Path
+from typing import Optional
+
+
+class SeverityLevel(Enum):
+    """Severity levels for issues."""
+
+    LOW = "low"
+    MEDIUM = "medium"
+    HIGH = "high"
+    CRITICAL = "critical"
+
+
+class IssueCategory(Enum):
+    """Categories of issues that can be detected."""
+
+    SECURITY = "security"
+    CODE_QUALITY = "code_quality"
+    ERROR_HANDLING = "error_handling"
+    ANTI_PATTERN = "anti_pattern"
+    COMPLEXITY = "complexity"
+    STYLE = "style"
+
+
+@dataclass
+class Issue:
+    """Represents a detected issue in the code."""
+
+    severity: SeverityLevel
+    category: IssueCategory
+    file_path: str
+    line_number: int
+    message: str
+    suggestion: Optional[str] = None
+    code_snippet: Optional[str] = None
+    scanner_name: str = "unknown"
+
+    def to_dict(self) -> dict:
+        """Convert issue to dictionary."""
+        return {
+            "severity": self.severity.value,
+            "category": self.category.value,
+            "file_path": self.file_path,
+            "line_number": self.line_number,
+            "message": self.message,
+            "suggestion": self.suggestion,
+            "code_snippet": self.code_snippet,
+            "scanner_name": self.scanner_name,
+        }
+
+
+@dataclass
+class ScanResult:
+    """Result of a code scan operation."""
+
+    files_scanned: int
+    issues: list[Issue] = field(default_factory=list)
+    warnings: list[str] = field(default_factory=list)
+    scan_time: datetime = field(default_factory=datetime.now)
+    target_path: str = ""
+
+    def add_issue(self, issue: Issue) -> None:
+        """Add an issue to the results."""
+        self.issues.append(issue)
+
+    def add_warning(self, warning: str) -> None:
+        """Add a warning to the results."""
+        self.warnings.append(warning)
+
+    def filter_by_severity(self, min_severity: SeverityLevel) -> "ScanResult":
+        """Filter issues by minimum severity level."""
+        severity_order = [
+            SeverityLevel.LOW,
+            SeverityLevel.MEDIUM,
+            SeverityLevel.HIGH,
+            SeverityLevel.CRITICAL,
+        ]
+        min_index = severity_order.index(min_severity)
+
+        filtered = ScanResult(
+            files_scanned=self.files_scanned,
+            target_path=self.target_path,
+        )
+        for issue in self.issues:
+            if severity_order.index(issue.severity) >= min_index:
+                filtered.add_issue(issue)
+        filtered.warnings = self.warnings.copy()
+        return filtered
+
+    def filter_by_category(self, categories: list[IssueCategory]) -> "ScanResult":
+        """Filter issues by categories."""
+        filtered = ScanResult(
+            files_scanned=self.files_scanned,
+            target_path=self.target_path,
+        )
+        category_set = set(categories)
+        for issue in self.issues:
+            if issue.category in category_set:
+                filtered.add_issue(issue)
+        filtered.warnings = self.warnings.copy()
+        return filtered
+
+    def get_summary(self) -> dict:
+        """Get a summary of the scan results."""
+        summary = {
+            "files_scanned": self.files_scanned,
+            "total_issues": len(self.issues),
+            "issues_by_severity": {},
+            "issues_by_category": {},
+        }
+
+        for issue in self.issues:
+            severity = issue.severity.value
+            category = issue.category.value
+            summary["issues_by_severity"][severity] = summary["issues_by_severity"].get(severity, 0) + 1
+            summary["issues_by_category"][category] = summary["issues_by_category"].get(category, 0) + 1
+
+        return summary
+
+    def to_dict(self) -> dict:
+        """Convert scan result to dictionary."""
+        return {
+            "files_scanned": self.files_scanned,
+            "issues": [issue.to_dict() for issue in self.issues],
+            "warnings": self.warnings,
+            "scan_time": self.scan_time.isoformat(),
+            "target_path": self.target_path,
+        }