diff --git a/tests/unit/test_spec_parser.py b/tests/unit/test_spec_parser.py
new file mode 100644
index 0000000..24dc453
--- /dev/null
+++ b/tests/unit/test_spec_parser.py
@@ -0,0 +1,173 @@
+"""Unit tests for the spec parser module."""
+import pytest
+import tempfile
+import json
+from pathlib import Path
+
+from api_testgen.core import SpecParser
+from api_testgen.core.exceptions import InvalidOpenAPISpecError, UnsupportedVersionError
+
+
+class TestSpecParser:
+    """Tests for SpecParser class."""
+
+    def test_load_valid_openapi_30_spec(self, temp_spec_file):
+        """Test loading a valid OpenAPI 3.0 specification."""
+        parser = SpecParser(temp_spec_file)
+        spec = parser.load()
+
+        assert spec is not None
+        assert parser.version == "3.0.0"
+        assert parser.base_path == ""
+        assert len(parser.servers) == 1
+
+    def test_load_valid_json_spec(self, temp_json_spec_file):
+        """Test loading a valid JSON OpenAPI specification."""
+        parser = SpecParser(temp_json_spec_file)
+        spec = parser.load()
+
+        assert spec is not None
+        assert parser.version == "3.0.0"
+
+    def test_get_info(self, temp_spec_file):
+        """Test extracting API info from spec."""
+        parser = SpecParser(temp_spec_file)
+        parser.load()
+
+        info = parser.get_info()
+
+        assert info["title"] == "Test Pet Store API"
+        assert info["version"] == "1.0.0"
+        assert "sample" in info["description"].lower()
+
+    def test_get_paths(self, temp_spec_file):
+        """Test extracting paths from spec."""
+        parser = SpecParser(temp_spec_file)
+        parser.load()
+
+        paths = parser.get_paths()
+
+        assert "/pets" in paths
+        assert "/pets/{petId}" in paths
+
+    def test_get_endpoints(self, temp_spec_file):
+        """Test extracting endpoints from spec."""
+        parser = SpecParser(temp_spec_file)
+        parser.load()
+
+        endpoints = parser.get_endpoints()
+
+        assert len(endpoints) == 4
+        assert any(e["method"] == "get" and e["path"] == "/pets" for e in endpoints)
+        assert any(e["method"] == "post" and e["path"] == "/pets" for e in endpoints)
+        assert any(e["method"] == "get" and e["path"] == "/pets/{petId}" for e in endpoints)
+        assert any(e["method"] == "delete" and e["path"] == "/pets/{petId}" for e in endpoints)
+
+    def test_get_security_schemes(self, temp_spec_file):
+        """Test extracting security schemes from spec."""
+        parser = SpecParser(temp_spec_file)
+        parser.load()
+
+        schemes = parser.get_security_schemes()
+
+        assert "ApiKeyAuth" in schemes
+        assert "BearerAuth" in schemes
+        assert schemes["ApiKeyAuth"]["type"] == "apiKey"
+        assert schemes["BearerAuth"]["type"] == "http"
+        assert schemes["BearerAuth"]["scheme"] == "bearer"
+
+    def test_get_definitions(self, temp_spec_file):
+        """Test extracting schema definitions from spec."""
+        parser = SpecParser(temp_spec_file)
+        parser.load()
+
+        definitions = parser.get_definitions()
+
+        assert "Pet" in definitions
+        assert definitions["Pet"]["type"] == "object"
+
+    def test_endpoint_with_parameters(self, temp_spec_file):
+        """Test endpoint parameter extraction."""
+        parser = SpecParser(temp_spec_file)
+        parser.load()
+
+        endpoints = parser.get_endpoints()
+
+        pets_endpoint = next(e for e in endpoints if e["path"] == "/pets" and e["method"] == "get")
+
+        assert len(pets_endpoint["parameters"]) == 2
+        assert any(p["name"] == "limit" and p["in"] == "query" for p in pets_endpoint["parameters"])
+        assert any(p["name"] == "status" and p["in"] == "query" for p in pets_endpoint["parameters"])
+
+    def test_endpoint_with_path_parameters(self, temp_spec_file):
+        """Test path parameter extraction."""
+        parser = SpecParser(temp_spec_file)
+        parser.load()
+
+        endpoints = parser.get_endpoints()
+
+        pet_endpoint = next(e for e in endpoints if e["path"] == "/pets/{petId}" and e["method"] == "get")
+
+        assert len(pet_endpoint["parameters"]) == 1
+        param = pet_endpoint["parameters"][0]
+        assert param["name"] == "petId"
+        assert param["in"] == "path"
+        assert param["required"] is True
+
+    def test_endpoint_with_request_body(self, temp_spec_file):
+        """Test request body extraction for OpenAPI 3.0."""
+        parser = SpecParser(temp_spec_file)
+        parser.load()
+
+        endpoints = parser.get_endpoints()
+
+        create_endpoint = next(e for e in endpoints if e["path"] == "/pets" and e["method"] == "post")
+
+        assert create_endpoint["request_body"] is not None
+        assert create_endpoint["request_body"]["required"] is True
+
+    def test_endpoint_with_responses(self, temp_spec_file):
+        """Test response extraction."""
+        parser = SpecParser(temp_spec_file)
+        parser.load()
+
+        endpoints = parser.get_endpoints()
+
+        pets_endpoint = next(e for e in endpoints if e["path"] == "/pets" and e["method"] == "get")
+
+        assert "200" in pets_endpoint["responses"]
+        assert pets_endpoint["responses"]["200"]["description"] == "A list of pets"
+
+    def test_to_dict(self, temp_spec_file):
+        """Test dictionary representation of parsed spec."""
+        parser = SpecParser(temp_spec_file)
+        parser.load()
+
+        spec_dict = parser.to_dict()
+
+        assert "version" in spec_dict
+        assert "info" in spec_dict
+        assert "paths" in spec_dict
+        assert "endpoints" in spec_dict
+        assert "security_schemes" in spec_dict
+        assert "definitions" in spec_dict
+
+    def test_nonexistent_file_raises_error(self):
+        """Test that nonexistent file raises InvalidOpenAPISpecError."""
+        parser = SpecParser("/nonexistent/path/spec.yaml")
+
+        with pytest.raises(InvalidOpenAPISpecError):
+            parser.load()
+
+    def test_invalid_yaml_raises_error(self):
+        """Test that invalid YAML raises InvalidOpenAPISpecError."""
+        with tempfile.NamedTemporaryFile(mode='w', suffix='.yaml', delete=False) as f:
+            f.write("invalid: yaml: content: [[[")
+            f.flush()
+
+            parser = SpecParser(Path(f.name))
+
+            with pytest.raises(InvalidOpenAPISpecError):
+                parser.load()
+
+            Path(f.name).unlink()