diff --git a/resources/clauses.js b/resources/clauses.js
index fc95dd4..bf89dc3 100644
--- a/resources/clauses.js
+++ b/resources/clauses.js
@@ -172,6 +172,22 @@ makeClause({
     }
 });
 
+makeClause({
+    name: "Griseous Orb Limitation",
+    description: "Giratina-O must have Griseous Orb, and other pokemon " +
+        "can't use it",
+    validateTeam : function(team) {
+        for (var i in team) {
+            var p = team[i];
+            if ((p.species == "Giratina-o") && (p.itemName != "Griseous Orb"))
+                return false;
+            if ((p.species != "Giratina-o") && (p.itemName == "Griseous Orb"))
+                return false;
+        }
+        return true;
+    }
+});
+
 makeClause({
     name : "Little Cup Clause",
     description : "Rules for the Little Cup metagame",
diff --git a/resources/items.js b/resources/items.js
index 63bd8b6..4c3685c 100644
--- a/resources/items.js
+++ b/resources/items.js
@@ -1009,3 +1009,17 @@ makeItem({
         return Type.GROUND;
     },
 });
+
+makeItem({
+    name : "Griseous Orb",
+    informRemoveItem : function() {
+        // Griseous Orb is usable by any pokemon in Gen 5, but cannot be
+        // tricked on or off Giratina (of any form)
+        // TODO: Prevent Griseous Orb from being tricked onto Giratina
+        var subject = this.subject;
+        if (subject.species == "Giratina-o") {
+            return true;
+        }
+        return false;
+    }
+});
\ No newline at end of file
diff --git a/resources/metagames.xml b/resources/metagames.xml
index 4a60786..816675a 100644
--- a/resources/metagames.xml
+++ b/resources/metagames.xml
@@ -42,6 +42,7 @@
         <clause>Classic Freeze Clause</clause>
         <clause>Strict Damage Clause</clause>
         <clause>Evasion Clause</clause>
+        <clause>Griseous Orb Limitation</clause>
     </clauses>
     <timer>
         <pool>300</pool>
@@ -64,6 +65,7 @@
         <clause>Classic Freeze Clause</clause>
         <clause>Strict Damage Clause</clause>
         <clause>Evasion Clause</clause>
+        <clause>Griseous Orb Limitation</clause>
     </clauses>
     <timer>
         <pool>300</pool>
@@ -98,6 +100,7 @@
         <clause>Item Clause</clause>
         <clause>Soul Dew Clause</clause>
         <clause>Strict Damage Clause</clause>
+        <clause>Griseous Orb Limitation</clause>
     </clauses>
     <timer>
         <pool>300</pool>