diff --git a/Libraries/LibGUI/ModelIndex.cpp b/Libraries/LibGUI/ModelIndex.cpp
index 1c31d3f3bf..982969f0c3 100644
--- a/Libraries/LibGUI/ModelIndex.cpp
+++ b/Libraries/LibGUI/ModelIndex.cpp
@@ -47,3 +47,17 @@ const LogStream& operator<<(const LogStream& stream, const ModelIndex& value)
 }
 
 }
+
+namespace AK {
+
+void Formatter<GUI::ModelIndex>::format(TypeErasedFormatParams& params, FormatBuilder& builder, const GUI::ModelIndex& value)
+{
+    Formatter<StringView> formatter { *this };
+
+    if (value.internal_data())
+        formatter.format(params, builder, String::formatted("ModelIndex({},{},{:p})", value.row(), value.column(), value.internal_data()));
+    else
+        formatter.format(params, builder, String::formatted("ModelIndex({},{})", value.row(), value.column()));
+}
+
+}
diff --git a/Libraries/LibGUI/ModelIndex.h b/Libraries/LibGUI/ModelIndex.h
index 6c2c449f8f..222ea7f1b7 100644
--- a/Libraries/LibGUI/ModelIndex.h
+++ b/Libraries/LibGUI/ModelIndex.h
@@ -80,8 +80,15 @@ const LogStream& operator<<(const LogStream&, const ModelIndex&);
 }
 
 namespace AK {
+
+template<>
+struct Formatter<GUI::ModelIndex> : Formatter<StringView> {
+    void format(TypeErasedFormatParams&, FormatBuilder&, const GUI::ModelIndex&);
+};
+
 template<>
 struct Traits<GUI::ModelIndex> : public GenericTraits<GUI::ModelIndex> {
     static unsigned hash(const GUI::ModelIndex& index) { return pair_int_hash(index.row(), index.column()); }
 };
+
 }