diff --git a/worldguard-legacy/src/main/java/com/sk89q/worldguard/protection/flags/FlagContext.java b/worldguard-legacy/src/main/java/com/sk89q/worldguard/protection/flags/FlagContext.java
index e48d1dad..57dc1530 100644
--- a/worldguard-legacy/src/main/java/com/sk89q/worldguard/protection/flags/FlagContext.java
+++ b/worldguard-legacy/src/main/java/com/sk89q/worldguard/protection/flags/FlagContext.java
@@ -22,6 +22,7 @@
 import com.google.common.collect.Maps;
 import com.sk89q.minecraft.util.commands.CommandException;
 import com.sk89q.worldguard.bukkit.WorldGuardPlugin;
+import org.bukkit.Bukkit;
 import org.bukkit.command.CommandSender;
 import org.bukkit.entity.Player;
 
@@ -156,8 +157,17 @@ public FlagContextBuilder setObject(String key, Object value) {
             return this;
         }
 
+        protected boolean tryAddToMap(String key, Object value) {
+            if (map.containsKey(key)) return false;
+            this.map.put(key, value);
+            return true;
+        }
+
         public FlagContext build() {
+            Bukkit.getServer().getPluginManager().callEvent(new FlagContextCreateEvent(this));
+
             return new FlagContext(sender, input, map);
         }
     }
+
 }
diff --git a/worldguard-legacy/src/main/java/com/sk89q/worldguard/protection/flags/FlagContextCreateEvent.java b/worldguard-legacy/src/main/java/com/sk89q/worldguard/protection/flags/FlagContextCreateEvent.java
new file mode 100644
index 00000000..2c2cf561
--- /dev/null
+++ b/worldguard-legacy/src/main/java/com/sk89q/worldguard/protection/flags/FlagContextCreateEvent.java
@@ -0,0 +1,56 @@
+/*
+ * WorldGuard, a suite of tools for Minecraft
+ * Copyright (C) sk89q <http://www.sk89q.com>
+ * Copyright (C) WorldGuard team and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by the
+ * Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.sk89q.worldguard.protection.flags;
+
+import com.sk89q.worldguard.protection.flags.FlagContext.FlagContextBuilder;
+import org.bukkit.event.Event;
+import org.bukkit.event.HandlerList;
+
+public class FlagContextCreateEvent extends Event {
+
+    private FlagContextBuilder builder;
+
+    public FlagContextCreateEvent(FlagContextBuilder builder) {
+        this.builder = builder;
+    }
+
+    /**
+     * Add an object to the flag context with the given key. Keys must be unique.
+     *
+     * @param key a unique string to identify the object
+     * @param value the object to store in the context
+     * @return true if added successfully, false if the key was already used
+     */
+    public boolean addObject(String key, Object value) {
+        return builder.tryAddToMap(key, value);
+    }
+
+    private static final HandlerList handlers = new HandlerList();
+
+    @Override
+    public HandlerList getHandlers() {
+        return handlers;
+    }
+
+    public static HandlerList getHandlerList() {
+        return handlers;
+    }
+
+}