diff --git a/apps/openmw/mwclass/npc.cpp b/apps/openmw/mwclass/npc.cpp
index db0a6460ce..e7f6cc5270 100644
--- a/apps/openmw/mwclass/npc.cpp
+++ b/apps/openmw/mwclass/npc.cpp
@@ -3,6 +3,8 @@
 
 #include <memory>
 
+#include <boost/algorithm/string.hpp>
+
 #include <OgreSceneNode.h>
 
 #include <components/esm/loadnpc.hpp>
@@ -56,13 +58,15 @@ namespace MWClass
             // NPC stats
             if (!ref->base->faction.empty())
             {
+                std::string faction = ref->base->faction;
+                boost::algorithm::to_lower(faction);
                 if(ref->base->npdt52.gold != -10)
                 {
-                    data->mNpcStats.mFactionRank[ref->base->faction] = (int)ref->base->npdt52.rank;
+                    data->mNpcStats.mFactionRank[faction] = (int)ref->base->npdt52.rank;
                 }
                 else
                 {
-                    data->mNpcStats.mFactionRank[ref->base->faction] = (int)ref->base->npdt12.rank;
+                    data->mNpcStats.mFactionRank[faction] = (int)ref->base->npdt12.rank;
                 }
             }
 
diff --git a/apps/openmw/mwdialogue/dialoguemanager.cpp b/apps/openmw/mwdialogue/dialoguemanager.cpp
index 2c4de7be19..dbd826127c 100644
--- a/apps/openmw/mwdialogue/dialoguemanager.cpp
+++ b/apps/openmw/mwdialogue/dialoguemanager.cpp
@@ -206,7 +206,7 @@ namespace MWDialogue
                     if(!NPCstats.mFactionRank.empty())
                     {
                         std::string NPCFaction = NPCstats.mFactionRank.begin()->first;
-                        if(PCstats.mFactionRank.find(NPCFaction) != PCstats.mFactionRank.end()) sameFaction = 1;
+                        if(PCstats.mFactionRank.find(toLower(NPCFaction)) != PCstats.mFactionRank.end()) sameFaction = 1;
                     }
                     if(!selectCompare<int,int>(comp,sameFaction,select.i)) return false;
                     }
@@ -525,7 +525,7 @@ namespace MWDialogue
 
             //MWWorld::Class npcClass = MWWorld::Class::get(actor);
             MWMechanics::NpcStats stats = MWWorld::Class::get(actor).getNpcStats(actor);
-            std::map<std::string,int>::iterator it = stats.mFactionRank.find(info.npcFaction);
+            std::map<std::string,int>::iterator it = stats.mFactionRank.find(toLower(info.npcFaction));
             if(it!=stats.mFactionRank.end())
             {
                 //check rank
@@ -542,7 +542,7 @@ namespace MWDialogue
         if(!info.pcFaction.empty())
         {
             MWMechanics::NpcStats stats = MWWorld::Class::get(MWBase::Environment::get().getWorld()->getPlayer().getPlayer()).getNpcStats(MWBase::Environment::get().getWorld()->getPlayer().getPlayer());
-            std::map<std::string,int>::iterator it = stats.mFactionRank.find(info.pcFaction);
+            std::map<std::string,int>::iterator it = stats.mFactionRank.find(toLower(info.pcFaction));
             if(it!=stats.mFactionRank.end())
             {
                 //check rank
diff --git a/apps/openmw/mwmechanics/npcstats.hpp b/apps/openmw/mwmechanics/npcstats.hpp
index feac5d4d3c..972863b728 100644
--- a/apps/openmw/mwmechanics/npcstats.hpp
+++ b/apps/openmw/mwmechanics/npcstats.hpp
@@ -20,6 +20,7 @@ namespace MWMechanics
     {
         // NPCs other than the player can only have one faction. But for the sake of consistency
         // we use the same data structure for the PC and the NPCs.
+        /// \note the faction key must be in lowercase
         std::map<std::string, int> mFactionRank;
 
         Stat<float> mSkill[27];
diff --git a/apps/openmw/mwscript/statsextensions.cpp b/apps/openmw/mwscript/statsextensions.cpp
index cad52e5930..d235192817 100644
--- a/apps/openmw/mwscript/statsextensions.cpp
+++ b/apps/openmw/mwscript/statsextensions.cpp
@@ -1,6 +1,8 @@
 
 #include "statsextensions.hpp"
 
+#include <boost/algorithm/string.hpp>
+
 #include <components/compiler/extensions.hpp>
 
 #include <components/interpreter/interpreter.hpp>
@@ -362,6 +364,7 @@ namespace MWScript
                         factionID = runtime.getStringLiteral (runtime[0].mInteger);
                         runtime.pop();
                     }
+                    boost::algorithm::to_lower(factionID);
                     if(factionID != "")
                     {
                         MWWorld::Ptr player = MWBase::Environment::get().getWorld()->getPlayer().getPlayer();
@@ -390,6 +393,7 @@ namespace MWScript
                         factionID = runtime.getStringLiteral (runtime[0].mInteger);
                         runtime.pop();
                     }
+                    boost::algorithm::to_lower(factionID);
                     if(factionID != "")
                     {
                         MWWorld::Ptr player = MWBase::Environment::get().getWorld()->getPlayer().getPlayer();
@@ -422,6 +426,7 @@ namespace MWScript
                         factionID = runtime.getStringLiteral (runtime[0].mInteger);
                         runtime.pop();
                     }
+                    boost::algorithm::to_lower(factionID);
                     if(factionID != "")
                     {
                         MWWorld::Ptr player = MWBase::Environment::get().getWorld()->getPlayer().getPlayer();
@@ -459,6 +464,7 @@ namespace MWScript
                             factionID = MWWorld::Class::get(ptr).getNpcStats(ptr).mFactionRank.begin()->first;
                         }
                     }
+                    boost::algorithm::to_lower(factionID);
                     MWWorld::Ptr player = MWBase::Environment::get().getWorld()->getPlayer().getPlayer();
                     if(factionID!="")
                     {