diff --git a/docs/Lua API.rst b/docs/Lua API.rst
index 6c4b7052e..0a253df9d 100644
--- a/docs/Lua API.rst	
+++ b/docs/Lua API.rst	
@@ -3797,6 +3797,7 @@ Native functions provided by the `buildingplan` plugin:
 
 * ``bool isPlannableBuilding(df::building_type type, int16_t subtype, int32_t custom)`` returns whether the building type is handled by buildingplan.
 * ``bool isPlanModeEnabled(df::building_type type, int16_t subtype, int32_t custom)`` returns whether the buildingplan UI is enabled for the specified building type.
+* ``bool isPlannedBuilding(df::building *bld)`` returns whether the given building is managed by buildingplan.
 * ``void addPlannedBuilding(df::building *bld)`` suspends the building jobs and adds the building to the monitor list.
 * ``void doCycle()`` runs a check for whether buildlings in the monitor list can be assigned items and unsuspended. This method runs automatically twice a game day, so you only need to call it directly if you want buildingplan to do a check right now.
 * ``void scheduleCycle()`` schedules a cycle to be run during the next non-paused game frame. Can be called multiple times while the game is paused and only one cycle will be scheduled.
diff --git a/plugins/buildingplan.cpp b/plugins/buildingplan.cpp
index dedc89f62..aab308a3d 100644
--- a/plugins/buildingplan.cpp
+++ b/plugins/buildingplan.cpp
@@ -1024,6 +1024,10 @@ static bool isPlannableBuilding(df::building_type type,
         toBuildingTypeKey(type, subtype, custom));
 }
 
+static bool isPlannedBuilding(df::building *bld) {
+    return !!planner.getPlannedBuilding(bld);
+}
+
 static void addPlannedBuilding(df::building *bld) {
     planner.addPlannedBuilding(bld);
 }
@@ -1049,6 +1053,7 @@ static void setSetting(std::string name, bool value) {
 DFHACK_PLUGIN_LUA_FUNCTIONS {
     DFHACK_LUA_FUNCTION(isPlanModeEnabled),
     DFHACK_LUA_FUNCTION(isPlannableBuilding),
+    DFHACK_LUA_FUNCTION(isPlannedBuilding),
     DFHACK_LUA_FUNCTION(addPlannedBuilding),
     DFHACK_LUA_FUNCTION(doCycle),
     DFHACK_LUA_FUNCTION(scheduleCycle),
diff --git a/plugins/lua/buildingplan.lua b/plugins/lua/buildingplan.lua
index 9659b4867..f640969b8 100644
--- a/plugins/lua/buildingplan.lua
+++ b/plugins/lua/buildingplan.lua
@@ -7,6 +7,7 @@ local _ENV = mkmodule('plugins.buildingplan')
  * void setSetting(string name, boolean value)
  * bool isPlanModeEnabled(df::building_type type, int16_t subtype, int32_t custom)
  * bool isPlannableBuilding(df::building_type type, int16_t subtype, int32_t custom)
+ * bool isPlannedBuilding(df::building *bld)
  * void addPlannedBuilding(df::building *bld)
  * void doCycle()
  * void scheduleCycle()