diff --git a/src/scanners/tree_sitter_scanner.py b/src/scanners/tree_sitter_scanner.py
new file mode 100644
index 0000000..8cdfab8
--- /dev/null
+++ b/src/scanners/tree_sitter_scanner.py
@@ -0,0 +1,248 @@
+"""Tree-sitter based pattern scanner for multi-language code analysis."""
+
+import re
+from pathlib import Path
+from typing import Optional
+
+from ..core.models import Issue, IssueCategory, SeverityLevel
+
+
+class TreeSitterScanner:
+    """Multi-language pattern scanner using Tree-sitter."""
+
+    CREDENTIAL_PATTERNS = [
+        (r"(?:api[_-]?key|apikey|secret|password|passwd|pwd|token|auth)\s*[:=]\s*['\"][a-zA-Z0-9_\-]{20,}['\"]",
+         "Potential hardcoded credential detected"),
+        (r"(?:aws[_-]?(?:access[_-]?key[_-]?id|secret[_-]?access[_-]?key))\s*[:=]\s*['\"][A-Z0-9]{20,}['\"]",
+         "Potential AWS credentials hardcoded"),
+        (r"['\"][A-Za-z0-9+\/]{40,}['\"]", "Potential API token or key detected"),
+        (r"(?:sk[_-]?live[_-]|[a-zA-Z0-9]{20,}[._]?)(?:secret|key|token)",
+         "Potential secret key detected"),
+        (r"ghp_[a-zA-Z0-9]{36}", "Potential GitHub PAT detected"),
+        (r"gho_[a-zA-Z0-9]{36}", "Potential GitHub OAuth token detected"),
+        (r"eyJ[a-zA-Z0-9_-]*\.eyJ[a-zA-Z0-9_-]*", "Potential JWT token detected"),
+    ]
+
+    SQL_INJECTION_PATTERNS = [
+        (r"['\"].*?(?:SELECT|INSERT|UPDATE|DELETE|DROP|ALTER).*?['\"].*?%", "Potential SQL injection - string formatting with user input"),
+        (r"(?:execute|exec)\s*\(\s*f?['\"].*?(?:SELECT|INSERT|UPDATE|DELETE)", "Potential SQL injection - f-string in SQL execution"),
+        (r"".*?".*\+.*?(?:user|input|param)", "Potential SQL injection - string concatenation"),
+        (r"format\s*\(\s*f?['\"].*?(?:SELECT|INSERT|UPDATE|DELETE)", "Potential SQL injection - format() with SQL"),
+    ]
+
+    COMMAND_INJECTION_PATTERNS = [
+        (r"os\.system\s*\(\s*f?['\"].*?['\"]", "Potential command injection - os.system with f-string"),
+        (r"subprocess\.(?:call|run|Popen)\s*\([^)]*shell\s*=\s*True", "Potential command injection - shell=True with user input"),
+        (r"eval\s*\(\s*f?['\"].*?['\"]", "Potential code injection - eval with f-string"),
+        (r"exec\s*\(\s*f?['\"].*?['\"]", "Potential code injection - exec with f-string"),
+    ]
+
+    MUTABLE_DEFAULT_PATTERNS = [
+        (r"def\s+\w+\s*\([^)]*=\s*\[", "Mutable default argument - use None and initialize inside"),
+        (r"def\s+\w+\s*\([^)]*=\s*\{", "Mutable default argument - use None and initialize inside"),
+    ]
+
+    ERROR_HANDLING_PATTERNS = [
+        (r"except\s*:\s*$", "Bare except clause - catch specific exceptions"),
+        (r"except\s+Exception\s*$", "Catch-all except Exception - catch specific exceptions"),
+        (r"try:\s*.*?except\s*:\s*pass", "Silent exception handling - at least log the error"),
+        (r"try:\s*.*?except\s+[^:]+:\s*pass", "Silent exception handling - at least log the error"),
+    ]
+
+    def __init__(self):
+        """Initialize the Tree-sitter scanner."""
+        self._parsers = {}
+
+    def scan_file(self, file_path: str) -> list[Issue]:
+        """Scan a single file for patterns."""
+        try:
+            path = Path(file_path)
+            if not path.exists():
+                return []
+
+            content = path.read_text(encoding="utf-8", errors="replace")
+            language = self._detect_language(file_path)
+            return self.scan_content(content, file_path, language)
+        except Exception:
+            return []
+
+    def scan_content(self, content: str, file_path: str, language: str) -> list[Issue]:
+        """Scan code content for patterns."""
+        issues = []
+
+        lines = content.split('\n')
+
+        issues.extend(self._scan_credential_patterns(content, file_path, lines))
+        issues.extend(self._scan_sql_injection_patterns(content, file_path, lines))
+        issues.extend(self._scan_command_injection_patterns(content, file_path, lines))
+
+        if language == "python":
+            issues.extend(self._scan_python_patterns(content, file_path, lines))
+
+        return issues
+
+    def _scan_credential_patterns(self, content: str, file_path: str, lines: list[str]) -> list[Issue]:
+        """Scan for hardcoded credentials."""
+        issues = []
+        for pattern, message in self.CREDENTIAL_PATTERNS:
+            for i, line in enumerate(lines, 1):
+                if re.search(pattern, line, re.IGNORECASE):
+                    if not self._is_false_positive(line):
+                        issues.append(Issue(
+                            severity=SeverityLevel.CRITICAL,
+                            category=IssueCategory.SECURITY,
+                            file_path=file_path,
+                            line_number=i,
+                            message=message,
+                            suggestion="Move credentials to environment variables or config file",
+                            scanner_name="tree-sitter",
+                        ))
+        return issues
+
+    def _scan_sql_injection_patterns(self, content: str, file_path: str, lines: list[str]) -> list[Issue]:
+        """Scan for SQL injection vulnerabilities."""
+        issues = []
+        for pattern, message in self.SQL_INJECTION_PATTERNS:
+            for i, line in enumerate(lines, 1):
+                if re.search(pattern, line, re.IGNORECASE):
+                    if not self._is_comment(line):
+                        issues.append(Issue(
+                            severity=SeverityLevel.HIGH,
+                            category=IssueCategory.SECURITY,
+                            file_path=file_path,
+                            line_number=i,
+                            message=message,
+                            suggestion="Use parameterized queries or ORM",
+                            scanner_name="tree-sitter",
+                        ))
+        return issues
+
+    def _scan_command_injection_patterns(self, content: str, file_path: str, lines: list[str]) -> list[Issue]:
+        """Scan for command injection vulnerabilities."""
+        issues = []
+        for pattern, message in self.COMMAND_INJECTION_PATTERNS:
+            for i, line in enumerate(lines, 1):
+                if re.search(pattern, line, re.IGNORECASE):
+                    if not self._is_comment(line):
+                        issues.append(Issue(
+                            severity=SeverityLevel.HIGH,
+                            category=IssueCategory.SECURITY,
+                            file_path=file_path,
+                            line_number=i,
+                            message=message,
+                            suggestion="Sanitize user input or use subprocess without shell=True",
+                            scanner_name="tree-sitter",
+                        ))
+        return issues
+
+    def _scan_python_patterns(self, content: str, file_path: str, lines: list[str]) -> list[Issue]:
+        """Scan for Python-specific patterns."""
+        issues = []
+
+        for pattern, message in self.MUTABLE_DEFAULT_PATTERNS:
+            for i, line in enumerate(lines, 1):
+                if re.search(pattern, line):
+                    issues.append(Issue(
+                        severity=SeverityLevel.MEDIUM,
+                        category=IssueCategory.ANTI_PATTERN,
+                        file_path=file_path,
+                        line_number=i,
+                        message=message,
+                        suggestion="Use None as default and initialize inside the function",
+                        scanner_name="tree-sitter",
+                    ))
+
+        for pattern, message in self.ERROR_HANDLING_PATTERNS:
+            for i, line in enumerate(lines, 1):
+                if re.search(pattern, line, re.IGNORECASE | re.MULTILINE):
+                    if not self._is_comment(line):
+                        issues.append(Issue(
+                            severity=SeverityLevel.LOW,
+                            category=IssueCategory.ERROR_HANDLING,
+                            file_path=file_path,
+                            line_number=i,
+                            message=message,
+                            suggestion="Catch specific exceptions and handle them appropriately",
+                            scanner_name="tree-sitter",
+                        ))
+
+        issues.extend(self._scan_complex_functions(content, file_path, lines))
+
+        return issues
+
+    def _scan_complex_functions(self, content: str, file_path: str, lines: list[str]) -> list[Issue]:
+        """Scan for overly complex functions."""
+        issues = []
+        in_function = False
+        function_lines = 0
+        function_start = 0
+        func_name = ""
+
+        for i, line in enumerate(lines, 1):
+            stripped = line.strip()
+
+            if in_function:
+                function_lines += 1
+
+                if function_lines > 50 and i == function_start + function_lines - 1:
+                    issues.append(Issue(
+                        severity=SeverityLevel.LOW,
+                        category=IssueCategory.COMPLEXITY,
+                        file_path=file_path,
+                        line_number=function_start,
+                        message=f"Function '{func_name}' is very long ({function_lines} lines)",
+                        suggestion="Consider breaking this function into smaller ones",
+                        scanner_name="tree-sitter",
+                    ))
+                    in_function = False
+
+                if stripped.startswith('def ') or stripped.startswith('async def '):
+                    in_function = False
+
+                if stripped and not stripped.startswith(' ') and not stripped.startswith('\t'):
+                    if not stripped.startswith('#'):
+                        in_function = False
+
+            if stripped.startswith('def ') or stripped.startswith('async def '):
+                match = re.match(r'(?:async\s+)?def\s+(\w+)', stripped)
+                if match:
+                    func_name = match.group(1)
+                    function_start = i
+                    function_lines = 1
+                    in_function = True
+
+        return issues
+
+    def _is_false_positive(self, line: str) -> bool:
+        """Check if a line is likely a false positive."""
+        false_positive_indicators = [
+            'example', 'placeholder', 'test', 'fake', 'demo', 'mock',
+            'your_', 'YOUR_', 'TODO', 'FIXME', 'XXX',
+        ]
+        line_lower = line.lower()
+        return any(indicator in line_lower for indicator in false_positive_indicators)
+
+    def _is_comment(self, line: str) -> bool:
+        """Check if a line is a comment."""
+        stripped = line.strip()
+        return stripped.startswith('#')
+
+    def _detect_language(self, file_path: str) -> str:
+        """Detect the programming language from file path."""
+        ext = Path(file_path).suffix.lower()
+        language_map = {
+            ".py": "python",
+            ".js": "javascript",
+            ".ts": "typescript",
+            ".tsx": "typescript",
+            ".jsx": "javascript",
+        }
+        return language_map.get(ext, "unknown")
+
+    def get_plugin_info(self) -> dict:
+        """Get information about the Tree-sitter scanner."""
+        return {
+            "name": "tree-sitter",
+            "version": "0.25.2",
+            "description": "Multi-language pattern scanner for code analysis",
+        }