diff --git a/modules/juce_audio_processors/format_types/LV2_SDK/README.md b/modules/juce_audio_processors/format_types/LV2_SDK/README.md
index e4b02ab560..7d6e748919 100644
--- a/modules/juce_audio_processors/format_types/LV2_SDK/README.md
+++ b/modules/juce_audio_processors/format_types/LV2_SDK/README.md
@@ -7,6 +7,8 @@ directory. The following modifications were made:
 - Removed the include of dlfcn.h in world.c
 - Fixed a leak of world->opt.lv2_path when calling lilv_world_set_option
   multiple times
+- Fixed a leak of plugin classes when calling lilv_world_load_plugin_classes
+  multiple times
 
 Remember to update the versions in the config headers if you ever update the
 library versions!
diff --git a/modules/juce_audio_processors/format_types/LV2_SDK/lilv/src/world.c b/modules/juce_audio_processors/format_types/LV2_SDK/lilv/src/world.c
index 3a601ab85c..5f1818dc7a 100644
--- a/modules/juce_audio_processors/format_types/LV2_SDK/lilv/src/world.c
+++ b/modules/juce_audio_processors/format_types/LV2_SDK/lilv/src/world.c
@@ -1046,7 +1046,8 @@ lilv_world_load_plugin_classes(LilvWorld* world)
     LilvPluginClass* pclass = lilv_plugin_class_new(
       world, parent, class_node, (const char*)sord_node_get_string(label));
     if (pclass) {
-      zix_tree_insert((ZixTree*)world->plugin_classes, pclass, NULL);
+      if (zix_tree_insert((ZixTree*)world->plugin_classes, pclass, NULL) == ZIX_STATUS_EXISTS)
+        lilv_plugin_class_free(pclass);
     }
 
     sord_node_free(world->world, label);