diff --git a/src/server/scripts/Northrend/Ulduar/Ulduar/boss_algalon_the_observer.cpp b/src/server/scripts/Northrend/Ulduar/Ulduar/boss_algalon_the_observer.cpp
index 4776c95ac8..6f87d7fcd2 100644
--- a/src/server/scripts/Northrend/Ulduar/Ulduar/boss_algalon_the_observer.cpp
+++ b/src/server/scripts/Northrend/Ulduar/Ulduar/boss_algalon_the_observer.cpp
@@ -18,6 +18,7 @@
 #include "ObjectMgr.h"
 #include "ScriptMgr.h"
 #include "ScriptedCreature.h"
+#include "SpellScript.h"
 #include "PassiveAI.h"
 #include "GameObjectAI.h"
 #include "MapManager.h"