diff --git a/Libraries/LibIDL/IDLParser.cpp b/Libraries/LibIDL/IDLParser.cpp
index 4f76b867896..3d6ddb087d8 100644
--- a/Libraries/LibIDL/IDLParser.cpp
+++ b/Libraries/LibIDL/IDLParser.cpp
@@ -813,6 +813,17 @@ void Parser::parse_interface(Interface& interface)
     consume_whitespace();
 }
 
+void Parser::parse_partial_interface(Interface& parent)
+{
+    assert_string("partial"sv);
+    consume_whitespace();
+    assert_string("interface"sv);
+
+    auto partial_interface = make<Interface>();
+    parse_interface(*partial_interface);
+    parent.partial_interfaces.append(move(partial_interface));
+}
+
 void Parser::parse_namespace(Interface& interface)
 {
     consume_whitespace();
@@ -1051,6 +1062,8 @@ void Parser::parse_non_interface_entities(bool allow_interface, Interface& inter
             parse_enumeration(extended_attributes, interface);
         } else if (lexer.next_is("typedef")) {
             parse_typedef(interface);
+        } else if (lexer.next_is("partial interface"sv)) {
+            parse_partial_interface(interface);
         } else if (lexer.next_is("interface mixin")) {
             parse_interface_mixin(interface);
         } else if (lexer.next_is("callback")) {
@@ -1183,6 +1196,11 @@ Interface& Parser::parse()
 
     for (auto& import : imports) {
         // FIXME: Instead of copying every imported entity into the current interface, query imports directly
+        for (auto& partial_interface : import.partial_interfaces) {
+            if (partial_interface->name == interface.name)
+                interface.extend_with_partial_interface(*partial_interface);
+        }
+
         for (auto& dictionary : import.dictionaries)
             interface.dictionaries.set(dictionary.key, dictionary.value);
 
diff --git a/Libraries/LibIDL/IDLParser.h b/Libraries/LibIDL/IDLParser.h
index 9537162726b..3b2a6e818e7 100644
--- a/Libraries/LibIDL/IDLParser.h
+++ b/Libraries/LibIDL/IDLParser.h
@@ -45,6 +45,7 @@ private:
     HashMap<ByteString, ByteString> parse_extended_attributes();
     void parse_attribute(HashMap<ByteString, ByteString>& extended_attributes, Interface&, IsStatic is_static = IsStatic::No);
     void parse_interface(Interface&);
+    void parse_partial_interface(Interface& parent);
     void parse_namespace(Interface&);
     void parse_non_interface_entities(bool allow_interface, Interface&);
     void parse_enumeration(HashMap<ByteString, ByteString>, Interface&);
diff --git a/Libraries/LibIDL/Types.cpp b/Libraries/LibIDL/Types.cpp
index c9c58b0e3c1..aaaf21e86de 100644
--- a/Libraries/LibIDL/Types.cpp
+++ b/Libraries/LibIDL/Types.cpp
@@ -305,4 +305,13 @@ void EffectiveOverloadSet::remove_all_other_entries()
     m_items = move(new_items);
 }
 
+void Interface::extend_with_partial_interface(Interface const& partial)
+{
+    attributes.extend(partial.attributes);
+    static_attributes.extend(partial.static_attributes);
+    constants.extend(partial.constants);
+    functions.extend(partial.functions);
+    static_functions.extend(partial.static_functions);
+}
+
 }
diff --git a/Libraries/LibIDL/Types.h b/Libraries/LibIDL/Types.h
index 8249219cad6..b53a27122d4 100644
--- a/Libraries/LibIDL/Types.h
+++ b/Libraries/LibIDL/Types.h
@@ -318,6 +318,7 @@ public:
     HashMap<ByteString, HashTable<ByteString>> included_mixins;
 
     ByteString module_own_path;
+    Vector<NonnullOwnPtr<Interface>> partial_interfaces;
     Vector<Interface&> imported_modules;
 
     HashMap<ByteString, Vector<Function&>> overload_sets;
@@ -337,6 +338,8 @@ public:
     {
         return !name.is_empty() || any_of(enumerations, [](auto& entry) { return entry.value.is_original_definition; });
     }
+
+    void extend_with_partial_interface(Interface const&);
 };
 
 class UnionType : public Type {