diff --git a/src/Tapper/RoslynExtensions.TypeCollector.cs b/src/Tapper/RoslynExtensions.TypeCollector.cs
index fe78f4f..a923165 100644
--- a/src/Tapper/RoslynExtensions.TypeCollector.cs
+++ b/src/Tapper/RoslynExtensions.TypeCollector.cs
@@ -87,6 +87,7 @@ public static INamedTypeSymbol[] GetSourceTypes(this Compilation compilation, bo
 
                 return false;
             })
+            .Distinct<INamedTypeSymbol>(SymbolEqualityComparer.Default)
             .ToArray();
 
         return TargetTypes;
diff --git a/tests/Tapper.Test.SourceTypes/PartialClass.cs b/tests/Tapper.Test.SourceTypes/PartialClass.cs
new file mode 100644
index 0000000..0537f00
--- /dev/null
+++ b/tests/Tapper.Test.SourceTypes/PartialClass.cs
@@ -0,0 +1,12 @@
+namespace Tapper.Test.SourceTypes;
+
+[TranspilationSource]
+public partial class PartialClass
+{
+    public int Value1 { get; set; }
+}
+
+public partial class PartialClass
+{
+    public int Value2 { get; set; }
+}
diff --git a/tests/Tapper.Tests/CompilationSingleton.cs b/tests/Tapper.Tests/CompilationSingleton.cs
index c8d7bc0..908c538 100644
--- a/tests/Tapper.Tests/CompilationSingleton.cs
+++ b/tests/Tapper.Tests/CompilationSingleton.cs
@@ -56,6 +56,10 @@ static CompilationSingleton()
             File.ReadAllText("../../../../Tapper.Test.SourceTypes/MessagePackAttributes.cs"),
             options);
 
+        var partialClassSyntax = CSharpSyntaxTree.ParseText(
+            File.ReadAllText("../../../../Tapper.Test.SourceTypes/PartialClass.cs"),
+            options);
+
         var compilationOptions = new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary)
             .WithNullableContextOptions(NullableContextOptions.Enable);
 
@@ -82,6 +86,7 @@ static CompilationSingleton()
                 inheritanceSyntax,
                 attributeAnnotatedSyntax,
                 messagePackAttributesSyntax,
+                partialClassSyntax
             },
             references: references,
             options: compilationOptions);
diff --git a/tests/Tapper.Tests/PartialClassTest.cs b/tests/Tapper.Tests/PartialClassTest.cs
new file mode 100644
index 0000000..d141a1e
--- /dev/null
+++ b/tests/Tapper.Tests/PartialClassTest.cs
@@ -0,0 +1,56 @@
+using Tapper.Test.SourceTypes;
+using Xunit;
+using Xunit.Abstractions;
+
+namespace Tapper.Tests;
+
+public class PartialClassTest
+{
+    private readonly ITestOutputHelper _output;
+
+    public PartialClassTest(ITestOutputHelper output)
+    {
+        _output = output;
+    }
+
+    [Fact]
+    public void Test()
+    {
+        var compilation = CompilationSingleton.Compilation;
+
+        var options = new TranspilationOptions(
+            compilation,
+            SerializerOption.Json,
+            NamingStyle.CamelCase,
+            EnumStyle.Value,
+            NewLineOption.Lf,
+            2,
+            false,
+            true
+        );
+
+        var codeGenerator = new TypeScriptCodeGenerator(compilation, options);
+
+        var type = typeof(PartialClass);
+        var typeSymbol = compilation.GetTypeByMetadataName(type.FullName!)!;
+
+        var writer = new CodeWriter();
+
+        codeGenerator.AddType(typeSymbol, ref writer);
+
+        var code = writer.ToString();
+        var gt = @"/** Transpiled from Tapper.Test.SourceTypes.PartialClass */
+export type PartialClass = {
+  /** Transpiled from int */
+  value1: number;
+  /** Transpiled from int */
+  value2: number;
+}
+";
+
+        _output.WriteLine(code);
+        _output.WriteLine(gt);
+
+        Assert.Equal(gt, code, ignoreLineEndingDifferences: true);
+    }
+}