diff --git a/PCTTools.Sample/SAssemblyCatalog/Misc/InterfaceDemo.cs b/PCTTools.Sample/SAssemblyCatalog/Misc/InterfaceDemo.cs
new file mode 100644
index 0000000..e72a3a7
--- /dev/null
+++ b/PCTTools.Sample/SAssemblyCatalog/Misc/InterfaceDemo.cs
@@ -0,0 +1,22 @@
+namespace PCTTools.Sample.SAssemblyCatalog.Misc
+{
+    public interface IParentInterface
+    {
+        string ParentProp { get; set; }
+    }
+
+    public interface IParentBInterface
+    {
+        string ParentProp { get; set; }
+    }
+
+    public interface IChildInterface : IParentInterface
+    {
+        string ChildProp { get; set; }
+    }
+
+    public interface IChildMultiParentInterface : IParentInterface, IParentBInterface
+    {
+        string ChildProp { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/PCTTools.Tests/TAssemblyCatalog/BaseTypeTests.cs b/PCTTools.Tests/TAssemblyCatalog/BaseTypeTests.cs
new file mode 100644
index 0000000..64dac43
--- /dev/null
+++ b/PCTTools.Tests/TAssemblyCatalog/BaseTypeTests.cs
@@ -0,0 +1,41 @@
+using NUnit.Framework;
+using PCTTools.Sample.SAssemblyCatalog.Misc;
+
+namespace PCTTools.Tests.TAssemblyCatalog
+{
+
+    [TestFixture()]
+    public class BaseTypeTests
+    {
+        [Test()]
+        public void InterfaceBaseTypesTest()
+        {
+            var pct = new AssemblyCatalog();
+
+            pct.GenerateDocumentationFromAssembly(typeof(IParentInterface).Assembly);
+            Assert.That(pct.HasError, Is.False);
+
+            var childMultiParentInterface = pct.TypeDocumentations.First(x => x.IsInterface && x.ShortName == nameof(IChildMultiParentInterface));
+            Assert.That(childMultiParentInterface.BaseTypes.Count, Is.EqualTo(2), $"{nameof(IChildMultiParentInterface)} should have 2 parents");
+            Assert.That(childMultiParentInterface.BaseTypes, Does.Contain(typeof(IParentInterface).FullName));
+            Assert.That(childMultiParentInterface.BaseTypes, Does.Contain(typeof(IParentBInterface).FullName));
+
+            var childParentInterface = pct.TypeDocumentations.First(x => x.IsInterface && x.ShortName == nameof(IChildInterface));
+            Assert.That(childParentInterface.BaseTypes.Count, Is.EqualTo(1), $"{nameof(IChildInterface)} should have 1 parent");
+            Assert.That(childParentInterface.BaseTypes, Does.Contain(typeof(IParentInterface).FullName));
+
+            var doctype = pct.TypeDocumentations.First(t => t.Name.Equals(
+                typeof(IParentInterface).FullName));
+
+            Assert.That(doctype.IsInterface, Is.EqualTo(true), "IParentInterface should be an interface");
+            Assert.That(doctype.BaseTypes, Is.Not.Null, "BaseTypes should not be null");
+            Assert.That(doctype.BaseTypes, Is.Empty, "An interface with no parent should have no BaseTypes");
+
+            doctype = pct.TypeDocumentations.First(t => t.Name.Equals(
+                typeof(IChildInterface).FullName));
+
+            Assert.That(doctype.IsInterface, Is.EqualTo(true), "IChildInterface should be an interface");
+            Assert.That(doctype.BaseTypes, Is.Not.Null, "BaseTypes should not be null");
+        }
+    }
+}
\ No newline at end of file
diff --git a/PCTTools/AssemblyCatalog.cs b/PCTTools/AssemblyCatalog.cs
index df971d7..6f3e565 100644
--- a/PCTTools/AssemblyCatalog.cs
+++ b/PCTTools/AssemblyCatalog.cs
@@ -411,12 +411,22 @@ internal List<string> GetBaseTypes(Type type)
         {
             var baseTypes = new List<string>();
 
-            var baseType = type.BaseType;
-            while (baseType != null)
+            if (type.IsInterface)
             {
-                baseTypes.Add(baseType.FullName);
+                foreach (var iface in type.GetInterfaces())
+                {
+                    baseTypes.Add(iface.FullName);
+                }
+            }
+            else
+            {
+                var baseType = type.BaseType;
+                while (baseType != null)
+                {
+                    baseTypes.Add(baseType.FullName);
 
-                baseType = baseType.BaseType;
+                    baseType = baseType.BaseType;
+                }
             }
             return baseTypes;
         }