diff --git a/BannerlordModEditor.Common.Tests/Models/SubModule/SubModuleLoaderTests.cs b/BannerlordModEditor.Common.Tests/Models/SubModule/SubModuleLoaderTests.cs
new file mode 100644
index 0000000..de6379c
--- /dev/null
+++ b/BannerlordModEditor.Common.Tests/Models/SubModule/SubModuleLoaderTests.cs
@@ -0,0 +1,176 @@
+using System;
+using System.IO;
+using System.Threading.Tasks;
+using Xunit;
+using BannerlordModEditor.Common.Models.SubModule;
+
+namespace BannerlordModEditor.Common.Tests.Models.SubModule
+{
+    public class SubModuleLoaderTests
+    {
+        private readonly SubModuleLoader _loader;
+
+        public SubModuleLoaderTests()
+        {
+            _loader = new SubModuleLoader();
+        }
+
+        [Fact]
+        public void Load_ReturnsNullForNonExistentFile()
+        {
+            var result = _loader.Load("/nonexistent/path/SubModule.xml");
+            Assert.Null(result);
+        }
+
+        [Fact]
+        public async Task LoadAsync_ReturnsNullForNonExistentFile()
+        {
+            var result = await _loader.LoadAsync("/nonexistent/path/SubModule.xml");
+            Assert.Null(result);
+        }
+
+        [Fact]
+        public void Load_ReadsValidSubModuleXml()
+        {
+            var tempFile = Path.GetTempFileName();
+            var xml = @"<?xml version=""1.0"" encoding=""utf-8""?>
+<Module>
+  <Name>Test Mod</Name>
+  <Id>TestMod</Id>
+  <Version>v1.0.0</Version>
+  <SingleplayerModule>true</SingleplayerModule>
+  <MultiplayerModule>false</MultiplayerModule>
+  <DependedModules>
+    <Module Id=""Native""/>
+  </DependedModules>
+  <SubModules>
+    <SubModule>
+      <Name>TestSubModule</Name>
+      <DLLName>TestMod.dll</DLLName>
+      <SubModuleClassType>TestMod.SubModule</SubModuleClassType>
+      <IsOptional>false</IsOptional>
+      <IsTicked>true</IsTicked>
+      <Tags>
+        <Tag Key=""DedicatedServerType"" Value=""none""/>
+      </Tags>
+    </SubModule>
+  </SubModules>
+</Module>";
+
+            try
+            {
+                File.WriteAllText(tempFile, xml);
+
+                var result = _loader.Load(tempFile);
+
+                Assert.NotNull(result);
+                Assert.Equal("Test Mod", result.Name);
+                Assert.Equal("TestMod", result.Id);
+                Assert.Equal("v1.0.0", result.Version);
+                Assert.True(result.SingleplayerModule);
+                Assert.False(result.MultiplayerModule);
+                Assert.Single(result.DependedModules);
+                Assert.Equal("Native", result.DependedModules[0].Id);
+                Assert.Single(result.SubModules);
+                Assert.Equal("TestSubModule", result.SubModules[0].Name);
+                Assert.Equal("TestMod.dll", result.SubModules[0].DLLName);
+                Assert.Single(result.SubModules[0].Tags);
+                Assert.Equal("DedicatedServerType", result.SubModules[0].Tags[0].Key);
+                Assert.Equal("none", result.SubModules[0].Tags[0].Value);
+            }
+            finally
+            {
+                File.Delete(tempFile);
+            }
+        }
+
+        [Fact]
+        public void Save_CreatesValidXml()
+        {
+            var tempFile = Path.GetTempFileName();
+            var data = new SubModuleDO
+            {
+                Name = "Save Test Mod",
+                Id = "SaveTestMod",
+                Version = "v2.0.0",
+                SingleplayerModule = true,
+                MultiplayerModule = false,
+                DependedModules = new()
+                {
+                    new DependedModuleDO { Id = "Native" },
+                    new DependedModuleDO { Id = "Sandbox" }
+                },
+                SubModules = new()
+                {
+                    new SubModuleItemDO
+                    {
+                        Name = "SaveTestSubModule",
+                        DLLName = "SaveTestMod.dll",
+                        SubModuleClassType = "SaveTestMod.SubModule",
+                        IsOptional = false,
+                        IsTicked = true,
+                        Tags = new()
+                        {
+                            new SubModuleTagDO { Key = "DedicatedServerType", Value = "none" }
+                        }
+                    }
+                }
+            };
+
+            try
+            {
+                _loader.Save(data, tempFile);
+
+                Assert.True(File.Exists(tempFile));
+                var loadedData = _loader.Load(tempFile);
+                Assert.NotNull(loadedData);
+                Assert.Equal("Save Test Mod", loadedData.Name);
+                Assert.Equal("SaveTestMod", loadedData.Id);
+                Assert.Equal(2, loadedData.DependedModules.Count);
+                Assert.Single(loadedData.SubModules);
+            }
+            finally
+            {
+                File.Delete(tempFile);
+            }
+        }
+
+        [Fact]
+        public async Task SaveAsync_CreatesValidXml()
+        {
+            var tempFile = Path.GetTempFileName();
+            var data = _loader.CreateDefault("Async Test Mod", "AsyncTestMod");
+
+            try
+            {
+                await _loader.SaveAsync(data, tempFile);
+
+                Assert.True(File.Exists(tempFile));
+                var loadedData = await _loader.LoadAsync(tempFile);
+                Assert.NotNull(loadedData);
+                Assert.Equal("Async Test Mod", loadedData.Name);
+                Assert.Equal("AsyncTestMod", loadedData.Id);
+            }
+            finally
+            {
+                File.Delete(tempFile);
+            }
+        }
+
+        [Fact]
+        public void CreateDefault_CreatesValidDefault()
+        {
+            var result = _loader.CreateDefault("Default Test", "DefaultTest");
+
+            Assert.Equal("Default Test", result.Name);
+            Assert.Equal("DefaultTest", result.Id);
+            Assert.Equal("v1.0.0", result.Version);
+            Assert.True(result.SingleplayerModule);
+            Assert.False(result.MultiplayerModule);
+            Assert.Empty(result.DependedModules);
+            Assert.Empty(result.SubModules);
+            Assert.Empty(result.Xmls);
+            Assert.Empty(result.OptionalDependedModules);
+        }
+    }
+}
diff --git a/BannerlordModEditor.Common/Models/SubModule/SubModuleDO.cs b/BannerlordModEditor.Common/Models/SubModule/SubModuleDO.cs
new file mode 100644
index 0000000..d421c35
--- /dev/null
+++ b/BannerlordModEditor.Common/Models/SubModule/SubModuleDO.cs
@@ -0,0 +1,96 @@
+using System;
+using System.Collections.Generic;
+using System.Xml.Serialization;
+
+namespace BannerlordModEditor.Common.Models.SubModule
+{
+    [XmlRoot("Module")]
+    public class SubModuleDO
+    {
+        [XmlElement("Name")]
+        public string Name { get; set; } = string.Empty;
+
+        [XmlElement("Id")]
+        public string Id { get; set; } = string.Empty;
+
+        [XmlElement("Version")]
+        public string Version { get; set; } = string.Empty;
+
+        [XmlElement("SingleplayerModule")]
+        public bool SingleplayerModule { get; set; } = true;
+
+        [XmlElement("MultiplayerModule")]
+        public bool MultiplayerModule { get; set; }
+
+        [XmlArray("DependedModules")]
+        [XmlArrayItem("Module")]
+        public List<DependedModuleDO> DependedModules { get; set; } = new();
+
+        [XmlArray("SubModules")]
+        [XmlArrayItem("SubModule")]
+        public List<SubModuleItemDO> SubModules { get; set; } = new();
+
+        [XmlArray("Xmls")]
+        [XmlArrayItem("XmlNode")]
+        public List<XmlNodeDO> Xmls { get; set; } = new();
+
+        [XmlArray("OptionalDependedModules")]
+        [XmlArrayItem("Module")]
+        public List<OptionalDependedModuleDO> OptionalDependedModules { get; set; } = new();
+    }
+
+    public class DependedModuleDO
+    {
+        [XmlAttribute("Id")]
+        public string Id { get; set; } = string.Empty;
+    }
+
+    public class OptionalDependedModuleDO
+    {
+        [XmlAttribute("Id")]
+        public string Id { get; set; } = string.Empty;
+    }
+
+    public class SubModuleItemDO
+    {
+        [XmlElement("Name")]
+        public string Name { get; set; } = string.Empty;
+
+        [XmlElement("DLLName")]
+        public string DLLName { get; set; } = string.Empty;
+
+        [XmlElement("SubModuleClassType")]
+        public string SubModuleClassType { get; set; } = string.Empty;
+
+        [XmlElement("IsOptional")]
+        public bool IsOptional { get; set; }
+
+        [XmlElement("IsTicked")]
+        public bool IsTicked { get; set; } = true;
+
+        [XmlArray("Tags")]
+        [XmlArrayItem("Tag")]
+        public List<SubModuleTagDO> Tags { get; set; } = new();
+    }
+
+    public class SubModuleTagDO
+    {
+        [XmlAttribute("Key")]
+        public string Key { get; set; } = string.Empty;
+
+        [XmlAttribute("Value")]
+        public string Value { get; set; } = string.Empty;
+    }
+
+    public class XmlNodeDO
+    {
+        [XmlAttribute("Id")]
+        public string Id { get; set; } = string.Empty;
+
+        [XmlAttribute("Type")]
+        public string Type { get; set; } = string.Empty;
+
+        [XmlText]
+        public string Path { get; set; } = string.Empty;
+    }
+}
diff --git a/BannerlordModEditor.Common/Models/SubModule/SubModuleDTO.cs b/BannerlordModEditor.Common/Models/SubModule/SubModuleDTO.cs
new file mode 100644
index 0000000..268e4b9
--- /dev/null
+++ b/BannerlordModEditor.Common/Models/SubModule/SubModuleDTO.cs
@@ -0,0 +1,96 @@
+using System;
+using System.Collections.Generic;
+using System.Xml.Serialization;
+
+namespace BannerlordModEditor.Common.Models.SubModule
+{
+    [XmlRoot("Module")]
+    public class SubModuleDTO
+    {
+        [XmlElement("Name")]
+        public string Name { get; set; } = string.Empty;
+
+        [XmlElement("Id")]
+        public string Id { get; set; } = string.Empty;
+
+        [XmlElement("Version")]
+        public string Version { get; set; } = string.Empty;
+
+        [XmlElement("SingleplayerModule")]
+        public bool SingleplayerModule { get; set; } = true;
+
+        [XmlElement("MultiplayerModule")]
+        public bool MultiplayerModule { get; set; }
+
+        [XmlArray("DependedModules")]
+        [XmlArrayItem("Module")]
+        public List<DependedModuleDTO> DependedModules { get; set; } = new();
+
+        [XmlArray("SubModules")]
+        [XmlArrayItem("SubModule")]
+        public List<SubModuleItemDTO> SubModules { get; set; } = new();
+
+        [XmlArray("Xmls")]
+        [XmlArrayItem("XmlNode")]
+        public List<XmlNodeDTO> Xmls { get; set; } = new();
+
+        [XmlArray("OptionalDependedModules")]
+        [XmlArrayItem("Module")]
+        public List<OptionalDependedModuleDTO> OptionalDependedModules { get; set; } = new();
+    }
+
+    public class DependedModuleDTO
+    {
+        [XmlAttribute("Id")]
+        public string Id { get; set; } = string.Empty;
+    }
+
+    public class OptionalDependedModuleDTO
+    {
+        [XmlAttribute("Id")]
+        public string Id { get; set; } = string.Empty;
+    }
+
+    public class SubModuleItemDTO
+    {
+        [XmlElement("Name")]
+        public string Name { get; set; } = string.Empty;
+
+        [XmlElement("DLLName")]
+        public string DLLName { get; set; } = string.Empty;
+
+        [XmlElement("SubModuleClassType")]
+        public string SubModuleClassType { get; set; } = string.Empty;
+
+        [XmlElement("IsOptional")]
+        public bool IsOptional { get; set; }
+
+        [XmlElement("IsTicked")]
+        public bool IsTicked { get; set; } = true;
+
+        [XmlArray("Tags")]
+        [XmlArrayItem("Tag")]
+        public List<SubModuleTagDTO> Tags { get; set; } = new();
+    }
+
+    public class SubModuleTagDTO
+    {
+        [XmlAttribute("Key")]
+        public string Key { get; set; } = string.Empty;
+
+        [XmlAttribute("Value")]
+        public string Value { get; set; } = string.Empty;
+    }
+
+    public class XmlNodeDTO
+    {
+        [XmlAttribute("Id")]
+        public string Id { get; set; } = string.Empty;
+
+        [XmlAttribute("Type")]
+        public string Type { get; set; } = string.Empty;
+
+        [XmlText]
+        public string Path { get; set; } = string.Empty;
+    }
+}
diff --git a/BannerlordModEditor.Common/Models/SubModule/SubModuleLoader.cs b/BannerlordModEditor.Common/Models/SubModule/SubModuleLoader.cs
new file mode 100644
index 0000000..95d1af1
--- /dev/null
+++ b/BannerlordModEditor.Common/Models/SubModule/SubModuleLoader.cs
@@ -0,0 +1,107 @@
+using System;
+using System.IO;
+using System.Threading.Tasks;
+using System.Xml;
+using System.Xml.Serialization;
+
+namespace BannerlordModEditor.Common.Models.SubModule
+{
+    public interface ISubModuleLoader
+    {
+        Task<SubModuleDO?> LoadAsync(string filePath);
+        SubModuleDO? Load(string filePath);
+        Task SaveAsync(SubModuleDO data, string filePath);
+        void Save(SubModuleDO data, string filePath);
+        SubModuleDO CreateDefault(string modName, string modId);
+    }
+
+    public class SubModuleLoader : ISubModuleLoader
+    {
+        private readonly XmlSerializer _serializer;
+
+        public SubModuleLoader()
+        {
+            _serializer = new XmlSerializer(typeof(SubModuleDTO));
+        }
+
+        public async Task<SubModuleDO?> LoadAsync(string filePath)
+        {
+            return await Task.Run(() => Load(filePath));
+        }
+
+        public SubModuleDO? Load(string filePath)
+        {
+            if (!File.Exists(filePath))
+                return null;
+
+            try
+            {
+                using var stream = new FileStream(filePath, FileMode.Open, FileAccess.Read);
+                var dto = (SubModuleDTO?)_serializer.Deserialize(stream);
+                return dto != null ? SubModuleMapper.ToDO(dto) : null;
+            }
+            catch (Exception ex)
+            {
+                throw new InvalidOperationException($"Failed to load SubModule.xml from {filePath}: {ex.Message}", ex);
+            }
+        }
+
+        public async Task SaveAsync(SubModuleDO data, string filePath)
+        {
+            await Task.Run(() => Save(data, filePath));
+        }
+
+        public void Save(SubModuleDO data, string filePath)
+        {
+            if (data == null)
+                throw new ArgumentNullException(nameof(data));
+
+            try
+            {
+                var dto = SubModuleMapper.ToDTO(data);
+                var directory = Path.GetDirectoryName(filePath);
+                if (!string.IsNullOrEmpty(directory) && !Directory.Exists(directory))
+                {
+                    Directory.CreateDirectory(directory);
+                }
+
+                var settings = new XmlWriterSettings
+                {
+                    Indent = true,
+                    IndentChars = "  ",
+                    NewLineChars = "\n",
+                    OmitXmlDeclaration = false,
+                    Encoding = new System.Text.UTF8Encoding(false)
+                };
+
+                using var stream = new FileStream(filePath, FileMode.Create, FileAccess.Write);
+                using var writer = XmlWriter.Create(stream, settings);
+                
+                var namespaces = new XmlSerializerNamespaces();
+                namespaces.Add("", "");
+                
+                _serializer.Serialize(writer, dto, namespaces);
+            }
+            catch (Exception ex)
+            {
+                throw new InvalidOperationException($"Failed to save SubModule.xml to {filePath}: {ex.Message}", ex);
+            }
+        }
+
+        public SubModuleDO CreateDefault(string modName, string modId)
+        {
+            return new SubModuleDO
+            {
+                Name = modName,
+                Id = modId,
+                Version = "v1.0.0",
+                SingleplayerModule = true,
+                MultiplayerModule = false,
+                DependedModules = new(),
+                SubModules = new(),
+                Xmls = new(),
+                OptionalDependedModules = new()
+            };
+        }
+    }
+}
diff --git a/BannerlordModEditor.Common/Models/SubModule/SubModuleMapper.cs b/BannerlordModEditor.Common/Models/SubModule/SubModuleMapper.cs
new file mode 100644
index 0000000..840695e
--- /dev/null
+++ b/BannerlordModEditor.Common/Models/SubModule/SubModuleMapper.cs
@@ -0,0 +1,71 @@
+using System.Linq;
+
+namespace BannerlordModEditor.Common.Models.SubModule
+{
+    public static class SubModuleMapper
+    {
+        public static SubModuleDTO ToDTO(SubModuleDO source)
+        {
+            if (source == null)
+                return new SubModuleDTO();
+
+            return new SubModuleDTO
+            {
+                Name = source.Name,
+                Id = source.Id,
+                Version = source.Version,
+                SingleplayerModule = source.SingleplayerModule,
+                MultiplayerModule = source.MultiplayerModule,
+                DependedModules = source.DependedModules?.Select(d => new DependedModuleDTO { Id = d.Id }).ToList() ?? new(),
+                SubModules = source.SubModules?.Select(s => ToSubModuleItemDTO(s)).ToList() ?? new(),
+                Xmls = source.Xmls?.Select(x => new XmlNodeDTO { Id = x.Id, Type = x.Type, Path = x.Path }).ToList() ?? new(),
+                OptionalDependedModules = source.OptionalDependedModules?.Select(o => new OptionalDependedModuleDTO { Id = o.Id }).ToList() ?? new()
+            };
+        }
+
+        public static SubModuleDO ToDO(SubModuleDTO source)
+        {
+            if (source == null)
+                return new SubModuleDO();
+
+            return new SubModuleDO
+            {
+                Name = source.Name,
+                Id = source.Id,
+                Version = source.Version,
+                SingleplayerModule = source.SingleplayerModule,
+                MultiplayerModule = source.MultiplayerModule,
+                DependedModules = source.DependedModules?.Select(d => new DependedModuleDO { Id = d.Id }).ToList() ?? new(),
+                SubModules = source.SubModules?.Select(s => ToSubModuleItemDO(s)).ToList() ?? new(),
+                Xmls = source.Xmls?.Select(x => new XmlNodeDO { Id = x.Id, Type = x.Type, Path = x.Path }).ToList() ?? new(),
+                OptionalDependedModules = source.OptionalDependedModules?.Select(o => new OptionalDependedModuleDO { Id = o.Id }).ToList() ?? new()
+            };
+        }
+
+        private static SubModuleItemDTO ToSubModuleItemDTO(SubModuleItemDO source)
+        {
+            return new SubModuleItemDTO
+            {
+                Name = source.Name,
+                DLLName = source.DLLName,
+                SubModuleClassType = source.SubModuleClassType,
+                IsOptional = source.IsOptional,
+                IsTicked = source.IsTicked,
+                Tags = source.Tags?.Select(t => new SubModuleTagDTO { Key = t.Key, Value = t.Value }).ToList() ?? new()
+            };
+        }
+
+        private static SubModuleItemDO ToSubModuleItemDO(SubModuleItemDTO source)
+        {
+            return new SubModuleItemDO
+            {
+                Name = source.Name,
+                DLLName = source.DLLName,
+                SubModuleClassType = source.SubModuleClassType,
+                IsOptional = source.IsOptional,
+                IsTicked = source.IsTicked,
+                Tags = source.Tags?.Select(t => new SubModuleTagDO { Key = t.Key, Value = t.Value }).ToList() ?? new()
+            };
+        }
+    }
+}