diff --git a/tests/test_config.py b/tests/test_config.py
new file mode 100644
index 0000000..d9ef386
--- /dev/null
+++ b/tests/test_config.py
@@ -0,0 +1,223 @@
+"""Unit tests for configuration loading and validation."""
+
+import os
+import tempfile
+from pathlib import Path
+from unittest.mock import patch
+
+import pytest
+
+from dev_env_sync.core.config import ConfigLoader, ConfigSchema, ConfigParseError
+
+
+class TestConfigLoader:
+    """Tests for ConfigLoader class."""
+    
+    @pytest.fixture
+    def sample_yaml_content(self):
+        """Sample YAML configuration content."""
+        return '''
+version: "1.0"
+name: "Test Environment"
+description: "Test configuration"
+
+dotfiles:
+  bashrc:
+    source: ./dotfiles/.bashrc
+    target: ~/.bashrc
+    backup: true
+  vimrc:
+    source: ./dotfiles/.vimrc
+    target: ~/.vimrc
+
+shell:
+  shell: bash
+  merge_strategy: replace
+
+editors:
+  vscode:
+    settings:
+      settings_file: ./editors/vscode/settings.json
+    extensions:
+      - name: ms-python.python
+
+packages:
+  - name: brew
+    packages:
+      - git
+      - neovim
+
+backup:
+  enabled: true
+  directory: ~/.dev-env-sync-backups
+  timestamp_format: "%Y%m%d_%H%M%S"
+'''
+    
+    def test_load_valid_config(self, sample_yaml_content, temp_dir):
+        """Test loading a valid configuration file."""
+        config_file = temp_dir / "config.yml"
+        config_file.write_text(sample_yaml_content)
+        
+        loader = ConfigLoader(str(config_file))
+        config = loader.load()
+        
+        assert config is not None
+        assert config.version == "1.0"
+        assert config.name == "Test Environment"
+        assert len(config.dotfiles) == 2
+        assert "bashrc" in config.dotfiles
+        assert "vimrc" in config.dotfiles
+        
+    def test_load_minimal_config(self, temp_dir):
+        """Test loading a minimal configuration file."""
+        config_file = temp_dir / "minimal.yml"
+        config_file.write_text('version: "1.0"\nname: "Minimal"')
+        
+        loader = ConfigLoader(str(config_file))
+        config = loader.load()
+        
+        assert config is not None
+        assert config.version == "1.0"
+        assert config.name == "Minimal"
+        assert len(config.dotfiles) == 0
+    
+    def test_dotfiles_parsing(self, sample_yaml_content, temp_dir):
+        """Test parsing dotfiles configuration."""
+        config_file = temp_dir / "config.yml"
+        config_file.write_text(sample_yaml_content)
+        
+        loader = ConfigLoader(str(config_file))
+        config = loader.load()
+        
+        assert "bashrc" in config.dotfiles
+        bashrc = config.dotfiles["bashrc"]
+        assert bashrc.source == "./dotfiles/.bashrc"
+        assert bashrc.target == "~/.bashrc"
+        assert bashrc.backup == True
+        
+    def test_packages_parsing(self, sample_yaml_content, temp_dir):
+        """Test parsing packages configuration."""
+        config_file = temp_dir / "config.yml"
+        config_file.write_text(sample_yaml_content)
+        
+        loader = ConfigLoader(str(config_file))
+        config = loader.load()
+        
+        assert len(config.packages) == 1
+        brew_pkg = config.packages[0]
+        assert brew_pkg.name == "brew"
+        assert len(brew_pkg.packages) == 2
+        assert "git" in brew_pkg.packages
+        assert "neovim" in brew_pkg.packages
+    
+    def test_editors_parsing(self, sample_yaml_content, temp_dir):
+        """Test parsing editors configuration."""
+        config_file = temp_dir / "config.yml"
+        config_file.write_text(sample_yaml_content)
+        
+        loader = ConfigLoader(str(config_file))
+        config = loader.load()
+        
+        assert "vscode" in config.editors
+        vscode_config = config.editors["vscode"]
+        assert "extensions" in vscode_config
+        assert len(vscode_config["extensions"]) == 1
+    
+    def test_backup_config_parsing(self, sample_yaml_content, temp_dir):
+        """Test parsing backup configuration."""
+        config_file = temp_dir / "config.yml"
+        config_file.write_text(sample_yaml_content)
+        
+        loader = ConfigLoader(str(config_file))
+        config = loader.load()
+        
+        assert config.backup.enabled == True
+        assert config.backup.directory == "~/.dev-env-sync-backups"
+        assert config.backup.timestamp_format == "%Y%m%d_%H%M%S"
+    
+    def test_invalid_yaml(self, temp_dir):
+        """Test handling of invalid YAML."""
+        config_file = temp_dir / "invalid.yml"
+        config_file.write_text("invalid: yaml: content: [")
+        
+        loader = ConfigLoader(str(config_file))
+        
+        with pytest.raises(ConfigParseError):
+            loader.load()
+    
+    def test_nonexistent_file(self):
+        """Test handling of nonexistent configuration file."""
+        loader = ConfigLoader("/nonexistent/path/config.yml")
+        
+        with pytest.raises(ConfigParseError):
+            loader.load()
+    
+    def test_create_default_config(self):
+        """Test creating default configuration."""
+        config = ConfigLoader.create_default_config()
+        
+        assert config is not None
+        assert config.version == "1.0"
+        assert config.name == "My Dev Environment"
+        assert len(config.dotfiles) > 0
+        assert len(config.packages) > 0
+    
+    def test_config_to_dict(self, temp_dir):
+        """Test converting config to dictionary."""
+        config_file = temp_dir / "config.yml"
+        config_file.write_text('version: "1.0"\nname: "Test"')
+        
+        loader = ConfigLoader(str(config_file))
+        config = loader.load()
+        
+        config_dict = config.to_dict()
+        
+        assert isinstance(config_dict, dict)
+        assert config_dict["version"] == "1.0"
+        assert config_dict["name"] == "Test"
+
+
+class TestConfigValidation:
+    """Tests for configuration validation."""
+    
+    def test_valid_config_schema(self, temp_dir):
+        """Test that valid config matches schema."""
+        config_file = temp_dir / "valid.yml"
+        config_file.write_text('''
+version: "1.0"
+name: "Valid Test"
+description: "Testing validation"
+
+dotfiles:
+  test:
+    source: ./test
+    target: ~/.test
+    backup: true
+
+backup:
+  enabled: true
+  directory: ~/.test-backups
+''')
+        
+        loader = ConfigLoader(str(config_file))
+        config = loader.load()
+        
+        assert config.version == "1.0"
+        assert config.backup.enabled == True
+    
+    def test_string_dotfile_shorthand(self, temp_dir):
+        """Test string shorthand for dotfiles."""
+        config_file = temp_dir / "shorthand.yml"
+        config_file.write_text('''
+version: "1.0"
+
+dotfiles:
+  bashrc: ./bashrc
+''')
+        
+        loader = ConfigLoader(str(config_file))
+        config = loader.load()
+        
+        assert "bashrc" in config.dotfiles
+        assert config.dotfiles["bashrc"].source == "./bashrc"
+        assert config.dotfiles["bashrc"].target == "~/.bashrc"