diff --git a/TUnit.Core/SharedDataSources.cs b/TUnit.Core/SharedDataSources.cs
new file mode 100644
index 0000000000..27ec9236da
--- /dev/null
+++ b/TUnit.Core/SharedDataSources.cs
@@ -0,0 +1,216 @@
+using System.Diagnostics.CodeAnalysis;
+using TUnit.Core.Helpers;
+
+namespace TUnit.Core;
+
+/// <summary>
+/// Provides shared instance management for custom data sources.
+/// Use this class to implement custom data source attributes that need the same
+/// sharing behavior as <see cref="ClassDataSourceAttribute{T}"/>.
+/// </summary>
+public static class SharedDataSources
+{
+    /// <summary>
+    /// Gets or creates a shared instance based on the specified sharing type, using the default constructor.
+    /// </summary>
+    /// <typeparam name="T">The type of instance to get or create. Must have a parameterless constructor.</typeparam>
+    /// <param name="sharedType">How the instance should be shared across tests.</param>
+    /// <param name="dataGeneratorMetadata">The data generator metadata (used to extract the test class type).</param>
+    /// <param name="key">The sharing key (required for <see cref="SharedType.Keyed"/>).</param>
+    /// <returns>The shared or newly created instance.</returns>
+    /// <exception cref="ArgumentNullException">
+    /// Thrown when <paramref name="key"/> is null/empty and <paramref name="sharedType"/> is <see cref="SharedType.Keyed"/>.
+    /// </exception>
+    /// <exception cref="ArgumentOutOfRangeException">Thrown when <paramref name="sharedType"/> is not a valid value.</exception>
+    public static T GetOrCreate<T>(SharedType sharedType, DataGeneratorMetadata dataGeneratorMetadata, string? key = null) where T : new()
+    {
+        return GetOrCreate(sharedType, dataGeneratorMetadata, key, static () => new T());
+    }
+
+    /// <summary>
+    /// Gets or creates a shared instance based on the specified sharing type, using the default constructor.
+    /// </summary>
+    /// <typeparam name="T">The type of instance to get or create. Must have a parameterless constructor.</typeparam>
+    /// <param name="sharedType">How the instance should be shared across tests.</param>
+    /// <param name="testClassType">The test class type (required for <see cref="SharedType.PerClass"/>).</param>
+    /// <param name="key">The sharing key (required for <see cref="SharedType.Keyed"/>).</param>
+    /// <returns>The shared or newly created instance.</returns>
+    /// <exception cref="ArgumentNullException">
+    /// Thrown when <paramref name="testClassType"/> is null and <paramref name="sharedType"/> is <see cref="SharedType.PerClass"/> or <see cref="SharedType.PerAssembly"/>,
+    /// or when <paramref name="key"/> is null/empty and <paramref name="sharedType"/> is <see cref="SharedType.Keyed"/>.
+    /// </exception>
+    /// <exception cref="ArgumentOutOfRangeException">Thrown when <paramref name="sharedType"/> is not a valid value.</exception>
+    public static T GetOrCreate<T>(SharedType sharedType, Type? testClassType = null, string? key = null) where T : new()
+    {
+        return GetOrCreate(sharedType, testClassType, key, static () => new T());
+    }
+
+    /// <summary>
+    /// Gets or creates a shared instance based on the specified sharing type.
+    /// </summary>
+    /// <typeparam name="T">The type of instance to get or create.</typeparam>
+    /// <param name="sharedType">How the instance should be shared across tests.</param>
+    /// <param name="testClassType">The test class type (required for <see cref="SharedType.PerClass"/>).</param>
+    /// <param name="key">The sharing key (required for <see cref="SharedType.Keyed"/>).</param>
+    /// <param name="factory">A factory function to create the instance if not already cached.</param>
+    /// <returns>The shared or newly created instance.</returns>
+    /// <exception cref="ArgumentNullException">
+    /// Thrown when <paramref name="testClassType"/> is null and <paramref name="sharedType"/> is <see cref="SharedType.PerClass"/> or <see cref="SharedType.PerAssembly"/>,
+    /// or when <paramref name="key"/> is null/empty and <paramref name="sharedType"/> is <see cref="SharedType.Keyed"/>.
+    /// </exception>
+    /// <exception cref="ArgumentOutOfRangeException">Thrown when <paramref name="sharedType"/> is not a valid value.</exception>
+    public static T GetOrCreate<T>(SharedType sharedType, Type? testClassType, string? key, Func<T> factory)
+    {
+        _ = factory ?? throw new ArgumentNullException(nameof(factory));
+
+        return sharedType switch
+        {
+            SharedType.None => factory(),
+            SharedType.PerTestSession => (T)TestDataContainer.GetGlobalInstance(typeof(T), _ => factory()!)!,
+            SharedType.PerClass => GetForClass<T>(testClassType, factory),
+            SharedType.Keyed => GetForKey<T>(key, factory),
+            SharedType.PerAssembly => GetForAssembly<T>(testClassType, factory),
+            _ => throw new ArgumentOutOfRangeException(nameof(sharedType), sharedType, "Invalid SharedType value.")
+        };
+    }
+
+    /// <summary>
+    /// Gets or creates a shared instance based on the specified sharing type.
+    /// </summary>
+    /// <typeparam name="T">The type of instance to get or create.</typeparam>
+    /// <param name="sharedType">How the instance should be shared across tests.</param>
+    /// <param name="dataGeneratorMetadata">The data generator metadata (used to extract the test class type).</param>
+    /// <param name="key">The sharing key (required for <see cref="SharedType.Keyed"/>).</param>
+    /// <param name="factory">A factory function to create the instance if not already cached.</param>
+    /// <returns>The shared or newly created instance.</returns>
+    /// <exception cref="ArgumentNullException">
+    /// Thrown when <paramref name="key"/> is null/empty and <paramref name="sharedType"/> is <see cref="SharedType.Keyed"/>.
+    /// </exception>
+    /// <exception cref="ArgumentOutOfRangeException">Thrown when <paramref name="sharedType"/> is not a valid value.</exception>
+    public static T GetOrCreate<T>(SharedType sharedType, DataGeneratorMetadata dataGeneratorMetadata, string? key, Func<T> factory)
+    {
+        var testClassType = TestClassTypeHelper.GetTestClassType(dataGeneratorMetadata);
+        return GetOrCreate(sharedType, testClassType, key, factory);
+    }
+
+    /// <summary>
+    /// Gets or creates a shared instance based on the specified sharing type.
+    /// </summary>
+    /// <param name="sharedType">How the instance should be shared across tests.</param>
+    /// <param name="type">The type of instance to get or create.</param>
+    /// <param name="dataGeneratorMetadata">The data generator metadata (used to extract the test class type).</param>
+    /// <param name="key">The sharing key (required for <see cref="SharedType.Keyed"/>).</param>
+    /// <param name="factory">A factory function to create the instance if not already cached.</param>
+    /// <returns>The shared or newly created instance.</returns>
+    /// <exception cref="ArgumentNullException">
+    /// Thrown when <paramref name="key"/> is null/empty and <paramref name="sharedType"/> is <see cref="SharedType.Keyed"/>.
+    /// </exception>
+    /// <exception cref="ArgumentOutOfRangeException">Thrown when <paramref name="sharedType"/> is not a valid value.</exception>
+    public static object? GetOrCreate(
+        SharedType sharedType,
+        [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors)]
+        Type type,
+        DataGeneratorMetadata dataGeneratorMetadata,
+        string? key,
+        Func<object?> factory)
+    {
+        var testClassType = TestClassTypeHelper.GetTestClassType(dataGeneratorMetadata);
+        return GetOrCreate(sharedType, type, testClassType, key, factory);
+    }
+
+    /// <summary>
+    /// Gets or creates a shared instance based on the specified sharing type.
+    /// </summary>
+    /// <param name="sharedType">How the instance should be shared across tests.</param>
+    /// <param name="type">The type of instance to get or create.</param>
+    /// <param name="testClassType">The test class type (required for <see cref="SharedType.PerClass"/>).</param>
+    /// <param name="key">The sharing key (required for <see cref="SharedType.Keyed"/>).</param>
+    /// <param name="factory">A factory function to create the instance if not already cached.</param>
+    /// <returns>The shared or newly created instance.</returns>
+    /// <exception cref="ArgumentNullException">
+    /// Thrown when <paramref name="testClassType"/> is null and <paramref name="sharedType"/> is <see cref="SharedType.PerClass"/> or <see cref="SharedType.PerAssembly"/>,
+    /// or when <paramref name="key"/> is null/empty and <paramref name="sharedType"/> is <see cref="SharedType.Keyed"/>.
+    /// </exception>
+    /// <exception cref="ArgumentOutOfRangeException">Thrown when <paramref name="sharedType"/> is not a valid value.</exception>
+    public static object? GetOrCreate(
+        SharedType sharedType,
+        [DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors)]
+        Type type,
+        Type? testClassType,
+        string? key,
+        Func<object?> factory)
+    {
+        _ = type ?? throw new ArgumentNullException(nameof(type));
+        _ = factory ?? throw new ArgumentNullException(nameof(factory));
+
+        return sharedType switch
+        {
+            SharedType.None => factory(),
+            SharedType.PerTestSession => TestDataContainer.GetGlobalInstance(type, _ => factory()!),
+            SharedType.PerClass => GetForClass(type, testClassType, factory),
+            SharedType.Keyed => GetForKey(type, key, factory),
+            SharedType.PerAssembly => GetForAssembly(type, testClassType, factory),
+            _ => throw new ArgumentOutOfRangeException(nameof(sharedType), sharedType, "Invalid SharedType value.")
+        };
+    }
+
+    private static T GetForClass<T>(Type? testClassType, Func<T> factory)
+    {
+        if (testClassType is null)
+        {
+            throw new ArgumentNullException(nameof(testClassType), "testClassType is required when SharedType is PerClass.");
+        }
+
+        return (T)TestDataContainer.GetInstanceForClass(testClassType, typeof(T), _ => factory()!)!;
+    }
+
+    private static object? GetForClass(Type type, Type? testClassType, Func<object?> factory)
+    {
+        if (testClassType is null)
+        {
+            throw new ArgumentNullException(nameof(testClassType), "testClassType is required when SharedType is PerClass.");
+        }
+
+        return TestDataContainer.GetInstanceForClass(testClassType, type, _ => factory()!);
+    }
+
+    private static T GetForKey<T>(string? key, Func<T> factory)
+    {
+        if (string.IsNullOrEmpty(key))
+        {
+            throw new ArgumentNullException(nameof(key), "key is required when SharedType is Keyed.");
+        }
+
+        return (T)TestDataContainer.GetInstanceForKey(key!, typeof(T), _ => factory()!)!;
+    }
+
+    private static object? GetForKey(Type type, string? key, Func<object?> factory)
+    {
+        if (string.IsNullOrEmpty(key))
+        {
+            throw new ArgumentNullException(nameof(key), "key is required when SharedType is Keyed.");
+        }
+
+        return TestDataContainer.GetInstanceForKey(key!, type, _ => factory()!);
+    }
+
+    private static T GetForAssembly<T>(Type? testClassType, Func<T> factory)
+    {
+        if (testClassType is null)
+        {
+            throw new ArgumentNullException(nameof(testClassType), "testClassType is required when SharedType is PerAssembly.");
+        }
+
+        return (T)TestDataContainer.GetInstanceForAssembly(testClassType.Assembly, typeof(T), _ => factory()!)!;
+    }
+
+    private static object? GetForAssembly(Type type, Type? testClassType, Func<object?> factory)
+    {
+        if (testClassType is null)
+        {
+            throw new ArgumentNullException(nameof(testClassType), "testClassType is required when SharedType is PerAssembly.");
+        }
+
+        return TestDataContainer.GetInstanceForAssembly(testClassType.Assembly, type, _ => factory()!);
+    }
+}
diff --git a/TUnit.PublicAPI/Tests.Core_Library_Has_No_API_Changes.DotNet10_0.verified.txt b/TUnit.PublicAPI/Tests.Core_Library_Has_No_API_Changes.DotNet10_0.verified.txt
index 1ff9acff74..b08d85780f 100644
--- a/TUnit.PublicAPI/Tests.Core_Library_Has_No_API_Changes.DotNet10_0.verified.txt
+++ b/TUnit.PublicAPI/Tests.Core_Library_Has_No_API_Changes.DotNet10_0.verified.txt
@@ -1198,6 +1198,17 @@ namespace
         public string Key { get; init; }
         public  Type { get; init; }
     }
+    public static class SharedDataSources
+    {
+        public static object? GetOrCreate(.SharedType sharedType, [.(..None | ..PublicParameterlessConstructor | ..PublicConstructors | ..NonPublicConstructors)]  type, ? testClassType, string? key, <object?> factory) { }
+        public static object? GetOrCreate(.SharedType sharedType, [.(..None | ..PublicParameterlessConstructor | ..PublicConstructors | ..NonPublicConstructors)]  type, .DataGeneratorMetadata dataGeneratorMetadata, string? key, <object?> factory) { }
+        public static T GetOrCreate<T>(.SharedType sharedType, ? testClassType = null, string? key = null)
+            where T : new() { }
+        public static T GetOrCreate<T>(.SharedType sharedType, .DataGeneratorMetadata dataGeneratorMetadata, string? key = null)
+            where T : new() { }
+        public static T GetOrCreate<T>(.SharedType sharedType, ? testClassType, string? key, <T> factory) { }
+        public static T GetOrCreate<T>(.SharedType sharedType, .DataGeneratorMetadata dataGeneratorMetadata, string? key, <T> factory) { }
+    }
     public enum SharedType
     {
         None = 0,
diff --git a/TUnit.PublicAPI/Tests.Core_Library_Has_No_API_Changes.DotNet8_0.verified.txt b/TUnit.PublicAPI/Tests.Core_Library_Has_No_API_Changes.DotNet8_0.verified.txt
index 97a073cc98..2de5ad38a2 100644
--- a/TUnit.PublicAPI/Tests.Core_Library_Has_No_API_Changes.DotNet8_0.verified.txt
+++ b/TUnit.PublicAPI/Tests.Core_Library_Has_No_API_Changes.DotNet8_0.verified.txt
@@ -1198,6 +1198,17 @@ namespace
         public string Key { get; init; }
         public  Type { get; init; }
     }
+    public static class SharedDataSources
+    {
+        public static object? GetOrCreate(.SharedType sharedType, [.(..None | ..PublicParameterlessConstructor | ..PublicConstructors | ..NonPublicConstructors)]  type, ? testClassType, string? key, <object?> factory) { }
+        public static object? GetOrCreate(.SharedType sharedType, [.(..None | ..PublicParameterlessConstructor | ..PublicConstructors | ..NonPublicConstructors)]  type, .DataGeneratorMetadata dataGeneratorMetadata, string? key, <object?> factory) { }
+        public static T GetOrCreate<T>(.SharedType sharedType, ? testClassType = null, string? key = null)
+            where T : new() { }
+        public static T GetOrCreate<T>(.SharedType sharedType, .DataGeneratorMetadata dataGeneratorMetadata, string? key = null)
+            where T : new() { }
+        public static T GetOrCreate<T>(.SharedType sharedType, ? testClassType, string? key, <T> factory) { }
+        public static T GetOrCreate<T>(.SharedType sharedType, .DataGeneratorMetadata dataGeneratorMetadata, string? key, <T> factory) { }
+    }
     public enum SharedType
     {
         None = 0,
diff --git a/TUnit.PublicAPI/Tests.Core_Library_Has_No_API_Changes.DotNet9_0.verified.txt b/TUnit.PublicAPI/Tests.Core_Library_Has_No_API_Changes.DotNet9_0.verified.txt
index bd1f9325d5..bb8a1a6d3d 100644
--- a/TUnit.PublicAPI/Tests.Core_Library_Has_No_API_Changes.DotNet9_0.verified.txt
+++ b/TUnit.PublicAPI/Tests.Core_Library_Has_No_API_Changes.DotNet9_0.verified.txt
@@ -1198,6 +1198,17 @@ namespace
         public string Key { get; init; }
         public  Type { get; init; }
     }
+    public static class SharedDataSources
+    {
+        public static object? GetOrCreate(.SharedType sharedType, [.(..None | ..PublicParameterlessConstructor | ..PublicConstructors | ..NonPublicConstructors)]  type, ? testClassType, string? key, <object?> factory) { }
+        public static object? GetOrCreate(.SharedType sharedType, [.(..None | ..PublicParameterlessConstructor | ..PublicConstructors | ..NonPublicConstructors)]  type, .DataGeneratorMetadata dataGeneratorMetadata, string? key, <object?> factory) { }
+        public static T GetOrCreate<T>(.SharedType sharedType, ? testClassType = null, string? key = null)
+            where T : new() { }
+        public static T GetOrCreate<T>(.SharedType sharedType, .DataGeneratorMetadata dataGeneratorMetadata, string? key = null)
+            where T : new() { }
+        public static T GetOrCreate<T>(.SharedType sharedType, ? testClassType, string? key, <T> factory) { }
+        public static T GetOrCreate<T>(.SharedType sharedType, .DataGeneratorMetadata dataGeneratorMetadata, string? key, <T> factory) { }
+    }
     public enum SharedType
     {
         None = 0,
diff --git a/TUnit.PublicAPI/Tests.Core_Library_Has_No_API_Changes.Net4_7.verified.txt b/TUnit.PublicAPI/Tests.Core_Library_Has_No_API_Changes.Net4_7.verified.txt
index 08b1e25e4b..093c221195 100644
--- a/TUnit.PublicAPI/Tests.Core_Library_Has_No_API_Changes.Net4_7.verified.txt
+++ b/TUnit.PublicAPI/Tests.Core_Library_Has_No_API_Changes.Net4_7.verified.txt
@@ -1156,6 +1156,17 @@ namespace
         public string Key { get; init; }
         public  Type { get; init; }
     }
+    public static class SharedDataSources
+    {
+        public static object? GetOrCreate(.SharedType sharedType,  type, ? testClassType, string? key, <object?> factory) { }
+        public static object? GetOrCreate(.SharedType sharedType,  type, .DataGeneratorMetadata dataGeneratorMetadata, string? key, <object?> factory) { }
+        public static T GetOrCreate<T>(.SharedType sharedType, ? testClassType = null, string? key = null)
+            where T : new() { }
+        public static T GetOrCreate<T>(.SharedType sharedType, .DataGeneratorMetadata dataGeneratorMetadata, string? key = null)
+            where T : new() { }
+        public static T GetOrCreate<T>(.SharedType sharedType, ? testClassType, string? key, <T> factory) { }
+        public static T GetOrCreate<T>(.SharedType sharedType, .DataGeneratorMetadata dataGeneratorMetadata, string? key, <T> factory) { }
+    }
     public enum SharedType
     {
         None = 0,