diff --git a/tests/unit/test_parsers.py b/tests/unit/test_parsers.py
new file mode 100644
index 0000000..642577a
--- /dev/null
+++ b/tests/unit/test_parsers.py
@@ -0,0 +1,191 @@
+"""Unit tests for log parsers."""
+
+import pytest
+from loglens.parsers.base import LogFormat, ParsedLogEntry
+from loglens.parsers.json_parser import JSONParser
+from loglens.parsers.syslog_parser import SyslogParser
+from loglens.parsers.apache_parser import ApacheParser
+from loglens.parsers.factory import ParserFactory
+
+
+class TestJSONParser:
+    """Tests for JSON parser."""
+
+    def test_parse_valid_json(self):
+        """Test parsing valid JSON log entry."""
+        parser = JSONParser()
+        line = '{"timestamp": "2024-01-15T10:30:00Z", "level": "INFO", "message": "Test"}'
+
+        entry = parser.parse(line, 1)
+
+        assert entry is not None
+        assert entry.raw_line == line
+        assert entry.line_number == 1
+        assert entry.message == "Test"
+        assert entry.level == "INFO"
+
+    def test_can_parse_json(self):
+        """Test can_parse detection for JSON."""
+        parser = JSONParser()
+
+        assert parser.can_parse('{"key": "value"}')
+        assert parser.can_parse('[1, 2, 3]')
+        assert not parser.can_parse("not json")
+        assert not parser.can_parse("")
+
+    def test_parse_invalid_json(self):
+        """Test parsing invalid JSON returns error entry."""
+        parser = JSONParser()
+        line = '{"invalid": json}'
+
+        entry = parser.parse(line, 1)
+
+        assert entry is not None
+        assert entry.severity == "error"
+        assert "JSON parse error" in entry.message
+
+    def test_parse_batch(self):
+        """Test batch parsing."""
+        parser = JSONParser()
+        lines = [
+            '{"level": "INFO", "message": "First"}',
+            '{"level": "ERROR", "message": "Second"}',
+            '{"level": "INFO", "message": "Third"}',
+        ]
+
+        results = parser.parse_batch(lines)
+
+        assert len(results) == 3
+        assert results[0].message == "First"
+        assert results[1].message == "Second"
+        assert results[2].message == "Third"
+
+
+class TestSyslogParser:
+    """Tests for Syslog parser."""
+
+    def test_parse_rfc3164(self):
+        """Test parsing RFC 3164 syslog format."""
+        parser = SyslogParser()
+        line = "Jan 15 10:30:00 server-01 app[1234]: Test message"
+
+        entry = parser.parse(line, 1)
+
+        assert entry is not None
+        assert entry.host == "server-01"
+        assert entry.logger == "app[1234]"
+        assert entry.message == "Test message"
+
+    def test_can_parse_syslog(self):
+        """Test can_parse detection for syslog."""
+        parser = SyslogParser()
+
+        assert parser.can_parse("Jan 15 10:30:00 server-01 app: message")
+        assert parser.can_parse("<34>1 2024-01-15T10:30:00Z server-01 app - - - message")
+        assert not parser.can_parse("not syslog format")
+
+    def test_parse_priority(self):
+        """Test parsing priority from syslog."""
+        parser = SyslogParser()
+        line = "<34>1 2024-01-15T10:30:00Z server-01 app - - - message"
+
+        entry = parser.parse(line, 1)
+
+        assert entry is not None
+        assert entry.facility == "auth"
+
+
+class TestApacheParser:
+    """Tests for Apache/Nginx parser."""
+
+    def test_parse_combined_log(self):
+        """Test parsing Apache combined log format."""
+        parser = ApacheParser()
+        line = '192.168.1.1 - - [15/Jan/2024:10:30:00 +0000] "GET /api HTTP/1.1" 200 1234 "-" "Mozilla"'
+
+        entry = parser.parse(line, 1)
+
+        assert entry is not None
+        assert entry.host == "192.168.1.1"
+        assert entry.level == "info"
+        assert "GET /api" in entry.message
+
+    def test_can_parse_apache(self):
+        """Test can_parse detection for Apache logs."""
+        parser = ApacheParser()
+
+        assert parser.can_parse('192.168.1.1 - - [15/Jan/2024:10:30:00 +0000] "GET /" 200 1234')
+        assert not parser.can_parse("not apache format")
+
+    def test_error_log(self):
+        """Test parsing Apache error log."""
+        parser = ApacheParser()
+        line = '[Sat Jan 15 10:30:00.123456 2024] [mpm_prefork:notice] [pid 1234] AH00163: Apache configured'
+
+        entry = parser.parse(line, 1)
+
+        assert entry is not None
+        assert entry.level == "notice"
+
+    def test_status_code_inference(self):
+        """Test severity inference from HTTP status codes."""
+        parser = ApacheParser()
+
+        entry_500 = parser.parse('192.168.1.1 - - [15/Jan/2024:10:30:00 +0000] "GET /" 500 123', 1)
+        assert entry_500.level == "error"
+
+        entry_404 = parser.parse('192.168.1.1 - - [15/Jan/2024:10:30:00 +0000] "GET /" 404 123', 1)
+        assert entry_404.level == "warning"
+
+
+class TestParserFactory:
+    """Tests for ParserFactory."""
+
+    def test_detect_json_format(self):
+        """Test format detection for JSON logs."""
+        factory = ParserFactory()
+        line = '{"key": "value"}'
+
+        format_detected = factory.detect_format(line)
+
+        assert format_detected == LogFormat.JSON
+
+    def test_detect_syslog_format(self):
+        """Test format detection for syslog."""
+        factory = ParserFactory()
+        line = "Jan 15 10:30:00 server-01 app: message"
+
+        format_detected = factory.detect_format(line)
+
+        assert format_detected == LogFormat.SYSLOG
+
+    def test_detect_apache_format(self):
+        """Test format detection for Apache logs."""
+        factory = ParserFactory()
+        line = '192.168.1.1 - - [15/Jan/2024:10:30:00 +0000] "GET /" 200 123'
+
+        format_detected = factory.detect_format(line)
+
+        assert format_detected == LogFormat.APACHE
+
+    def test_parse_lines_with_auto_detection(self):
+        """Test parsing lines with auto format detection."""
+        factory = ParserFactory()
+        lines = [
+            '{"level": "INFO", "message": "Test"}',
+            '{"level": "ERROR", "message": "Error test"}',
+        ]
+
+        results = factory.parse_lines(lines)
+
+        assert len(results) == 2
+
+    def test_unknown_format(self):
+        """Test handling of unknown format."""
+        factory = ParserFactory()
+        lines = ["not a known format"]
+
+        results = factory.parse_lines(lines)
+
+        assert len(results) == 1
+        assert results[0].message == "Unknown format"