diff --git a/moses2/FF/StatefulFeatureFunction.h b/moses2/FF/StatefulFeatureFunction.h
index 7cb3eaae97..c88eddead9 100644
--- a/moses2/FF/StatefulFeatureFunction.h
+++ b/moses2/FF/StatefulFeatureFunction.h
@@ -5,8 +5,7 @@
  *      Author: hieu
  */
 
-#ifndef STATEFULFEATUREFUNCTION_H_
-#define STATEFULFEATUREFUNCTION_H_
+#pragma once
 
 #include "FeatureFunction.h"
 #include "FFState.h"
@@ -63,4 +62,3 @@ class StatefulFeatureFunction: public FeatureFunction
 
 }
 
-#endif /* STATEFULFEATUREFUNCTION_H_ */
diff --git a/moses2/FF/StatelessFeatureFunction.h b/moses2/FF/StatelessFeatureFunction.h
index 249e4fdfe4..0ad0aaba4f 100644
--- a/moses2/FF/StatelessFeatureFunction.h
+++ b/moses2/FF/StatelessFeatureFunction.h
@@ -5,8 +5,7 @@
  *      Author: hieu
  */
 
-#ifndef STATELESSFEATUREFUNCTION_H_
-#define STATELESSFEATUREFUNCTION_H_
+#pragma once
 
 #include "FeatureFunction.h"
 
@@ -22,4 +21,3 @@ class StatelessFeatureFunction: public FeatureFunction
 
 }
 
-#endif /* STATELESSFEATUREFUNCTION_H_ */
diff --git a/moses2/HypothesisColl.h b/moses2/HypothesisColl.h
index f00a2efb07..0c89e8382f 100644
--- a/moses2/HypothesisColl.h
+++ b/moses2/HypothesisColl.h
@@ -6,7 +6,6 @@
  */
 #pragma once
 #include <unordered_set>
-#include <boost/unordered_set.hpp>
 #include "HypothesisBase.h"
 #include "MemPoolAllocator.h"
 #include "Recycler.h"
diff --git a/moses2/Main.cpp b/moses2/Main.cpp
index cf833760aa..dfdb9de3a1 100644
--- a/moses2/Main.cpp
+++ b/moses2/Main.cpp
@@ -107,7 +107,7 @@ void Temp()
   Moses2::MemPool pool;
   Moses2::MemPoolAllocator<int> a(pool);
 
-  boost::unordered_set<int, boost::hash<int>, std::equal_to<int>, Moses2::MemPoolAllocator<int> > s(a);
+  std::unordered_set<int, boost::hash<int>, std::equal_to<int>, Moses2::MemPoolAllocator<int> > s(a);
   s.insert(3);
   s.insert(4);
   s.insert(3);
diff --git a/moses2/Phrase.h b/moses2/Phrase.h
index 1007014837..a6f4961848 100644
--- a/moses2/Phrase.h
+++ b/moses2/Phrase.h
@@ -7,6 +7,7 @@
 
 #pragma once
 
+#include <boost/functional/hash.hpp>
 #include <cstddef>
 #include <string>
 #include <sstream>
diff --git a/moses2/PhraseBased/CubePruningMiniStack/Misc.h b/moses2/PhraseBased/CubePruningMiniStack/Misc.h
index 4fc576cbaa..8e746a83ec 100644
--- a/moses2/PhraseBased/CubePruningMiniStack/Misc.h
+++ b/moses2/PhraseBased/CubePruningMiniStack/Misc.h
@@ -7,7 +7,7 @@
 #pragma once
 #include <boost/pool/pool_alloc.hpp>
 #include <boost/unordered_map.hpp>
-#include <boost/unordered_set.hpp>
+#include <unordered_set>
 #include <vector>
 #include <queue>
 #include "../../legacy/Range.h"
@@ -70,7 +70,7 @@ class CubeEdge
           std::vector<QueueItem*, MemPoolAllocator<QueueItem*> >, QueueItemOrderer> Queue;
 
   typedef std::pair<const CubeEdge*, int> SeenPositionItem;
-  typedef boost::unordered_set<SeenPositionItem, boost::hash<SeenPositionItem>,
+  typedef std::unordered_set<SeenPositionItem, boost::hash<SeenPositionItem>,
           std::equal_to<SeenPositionItem>, MemPoolAllocator<SeenPositionItem> > SeenPositions;
 
   const Hypotheses &hypos;
diff --git a/moses2/PhraseBased/CubePruningMiniStack/Search.cpp b/moses2/PhraseBased/CubePruningMiniStack/Search.cpp
index 74103d2119..785eff9262 100644
--- a/moses2/PhraseBased/CubePruningMiniStack/Search.cpp
+++ b/moses2/PhraseBased/CubePruningMiniStack/Search.cpp
@@ -110,7 +110,7 @@ void Search::Decode(size_t stackInd)
 
   /*
   cerr << "edges: ";
-  boost::unordered_set<const Bitmap*> uniqueBM;
+  std::unordered_set<const Bitmap*> uniqueBM;
   BOOST_FOREACH(CubeEdge *edge, edges) {
   uniqueBM.insert(&edge->newBitmap);
   //cerr << *edge << " ";
diff --git a/moses2/PhraseBased/CubePruningMiniStack/Stack.h b/moses2/PhraseBased/CubePruningMiniStack/Stack.h
index abd564b3f0..c3a14b222c 100644
--- a/moses2/PhraseBased/CubePruningMiniStack/Stack.h
+++ b/moses2/PhraseBased/CubePruningMiniStack/Stack.h
@@ -6,7 +6,6 @@
  */
 #pragma once
 #include <boost/unordered_map.hpp>
-#include <boost/unordered_set.hpp>
 #include <deque>
 #include "../Hypothesis.h"
 #include "../../TypeDef.h"
diff --git a/moses2/PhraseBased/Manager.cpp b/moses2/PhraseBased/Manager.cpp
index 28073d4f61..0a1f51dbd6 100644
--- a/moses2/PhraseBased/Manager.cpp
+++ b/moses2/PhraseBased/Manager.cpp
@@ -6,7 +6,7 @@
  */
 #include <boost/foreach.hpp>
 #include <boost/functional/hash.hpp>
-#include <boost/unordered_set.hpp>
+#include <unordered_set>
 #include <vector>
 #include <sstream>
 #include "Manager.h"
@@ -218,7 +218,7 @@ std::string Manager::OutputNBest()
 {
   arcLists.Sort();
 
-  boost::unordered_set<size_t> distinctHypos;
+  std::unordered_set<size_t> distinctHypos;
 
   TrellisPaths<TrellisPath> contenders;
   m_search->AddInitialTrellisPaths(contenders);
diff --git a/moses2/PhraseBased/Normal/Stack.h b/moses2/PhraseBased/Normal/Stack.h
index 4ad707ce41..62675a5c18 100644
--- a/moses2/PhraseBased/Normal/Stack.h
+++ b/moses2/PhraseBased/Normal/Stack.h
@@ -6,7 +6,6 @@
  */
 #pragma once
 
-#include <boost/unordered_set.hpp>
 #include <deque>
 #include "../Hypothesis.h"
 #include "../../TypeDef.h"
diff --git a/moses2/SCFG/Misc.h b/moses2/SCFG/Misc.h
index 27b9df79a4..6eb107499c 100644
--- a/moses2/SCFG/Misc.h
+++ b/moses2/SCFG/Misc.h
@@ -7,7 +7,7 @@
 #pragma once
 #include <vector>
 #include <queue>
-#include <boost/unordered_set.hpp>
+#include <unordered_set>
 #include "../HypothesisColl.h"
 #include "../Vector.h"
 #include "Hypothesis.h"
@@ -60,7 +60,7 @@ class SeenPositions
 
 
 protected:
-  typedef boost::unordered_set<const SeenPosition*,
+  typedef std::unordered_set<const SeenPosition*,
           UnorderedComparer<SeenPosition>, UnorderedComparer<SeenPosition> > Coll;
   Coll m_coll;
 };
diff --git a/moses2/SCFG/nbest/NBests.h b/moses2/SCFG/nbest/NBests.h
index 97fe9a025e..7cddec1be5 100644
--- a/moses2/SCFG/nbest/NBests.h
+++ b/moses2/SCFG/nbest/NBests.h
@@ -6,7 +6,7 @@
  */
 
 #pragma once
-#include <boost/unordered_set.hpp>
+#include <unordered_set>
 #include "NBest.h"
 
 namespace Moses2
@@ -18,7 +18,7 @@ class NBests
 {
 public:
   Contenders contenders;
-  boost::unordered_set<size_t> distinctHypos;
+  std::unordered_set<size_t> distinctHypos;
 
   NBests(const SCFG::Manager &mgr,
          const ArcList &arcList,
diff --git a/moses2/defer/CubePruningBitmapStack/Misc.h b/moses2/defer/CubePruningBitmapStack/Misc.h
index 355f8f4c25..e0acdcd1ab 100644
--- a/moses2/defer/CubePruningBitmapStack/Misc.h
+++ b/moses2/defer/CubePruningBitmapStack/Misc.h
@@ -7,7 +7,6 @@
 #pragma once
 #include <boost/pool/pool_alloc.hpp>
 #include <boost/unordered_map.hpp>
-#include <boost/unordered_set.hpp>
 #include <vector>
 #include <queue>
 #include "../../legacy/Range.h"
@@ -72,7 +71,7 @@ class CubeEdge
           QueueItemOrderer> Queue;
 
   typedef std::pair<const CubeEdge*, int> SeenPositionItem;
-  typedef boost::unordered_set<SeenPositionItem,
+  typedef std::unordered_set<SeenPositionItem,
           boost::hash<SeenPositionItem>,
           std::equal_to<SeenPositionItem> > SeenPositions;
 
diff --git a/moses2/defer/CubePruningBitmapStack/Search.cpp b/moses2/defer/CubePruningBitmapStack/Search.cpp
index 8c06f13402..19e2477969 100644
--- a/moses2/defer/CubePruningBitmapStack/Search.cpp
+++ b/moses2/defer/CubePruningBitmapStack/Search.cpp
@@ -96,7 +96,7 @@ void Search::Decode(size_t stackInd)
 
   /*
   cerr << "edges: ";
-  boost::unordered_set<const Bitmap*> uniqueBM;
+  std::unordered_set<const Bitmap*> uniqueBM;
   BOOST_FOREACH(CubeEdge *edge, edges) {
   	uniqueBM.insert(&edge->newBitmap);
   	//cerr << *edge << " ";
diff --git a/moses2/defer/CubePruningBitmapStack/Stack.h b/moses2/defer/CubePruningBitmapStack/Stack.h
index f052fab428..b4d6ee1be9 100644
--- a/moses2/defer/CubePruningBitmapStack/Stack.h
+++ b/moses2/defer/CubePruningBitmapStack/Stack.h
@@ -6,7 +6,6 @@
  */
 #pragma once
 #include <boost/unordered_map.hpp>
-#include <boost/unordered_set.hpp>
 #include <deque>
 #include "../Hypothesis.h"
 #include "../../TypeDef.h"
@@ -27,7 +26,7 @@ typedef Vector<const Hypothesis*>  Hypotheses;
 class MiniStack
 {
 public:
-  typedef boost::unordered_set<const Hypothesis*,
+  typedef std::unordered_set<const Hypothesis*,
           UnorderedComparer<Hypothesis>,
           UnorderedComparer<Hypothesis>
           > _HCType;
diff --git a/moses2/defer/CubePruningCardinalStack/Misc.h b/moses2/defer/CubePruningCardinalStack/Misc.h
index 9f5d28f1e7..d04c299d1a 100644
--- a/moses2/defer/CubePruningCardinalStack/Misc.h
+++ b/moses2/defer/CubePruningCardinalStack/Misc.h
@@ -7,7 +7,6 @@
 #pragma once
 #include <boost/pool/pool_alloc.hpp>
 #include <boost/unordered_map.hpp>
-#include <boost/unordered_set.hpp>
 #include <vector>
 #include <queue>
 #include "../../legacy/Range.h"
@@ -72,7 +71,7 @@ class CubeEdge
           QueueItemOrderer> Queue;
 
   typedef std::pair<const CubeEdge*, int> SeenPositionItem;
-  typedef boost::unordered_set<SeenPositionItem,
+  typedef std::unordered_set<SeenPositionItem,
           boost::hash<SeenPositionItem>,
           std::equal_to<SeenPositionItem>
           > SeenPositions;
diff --git a/moses2/defer/CubePruningCardinalStack/Search.cpp b/moses2/defer/CubePruningCardinalStack/Search.cpp
index 23cae74ebc..6f72a53f8d 100644
--- a/moses2/defer/CubePruningCardinalStack/Search.cpp
+++ b/moses2/defer/CubePruningCardinalStack/Search.cpp
@@ -96,7 +96,7 @@ void Search::Decode(size_t stackInd)
 
   /*
   cerr << "edges: ";
-  boost::unordered_set<const Bitmap*> uniqueBM;
+  std::unordered_set<const Bitmap*> uniqueBM;
   BOOST_FOREACH(CubeEdge *edge, edges) {
   	uniqueBM.insert(&edge->newBitmap);
   	//cerr << *edge << " ";
diff --git a/moses2/defer/CubePruningCardinalStack/Stack.h b/moses2/defer/CubePruningCardinalStack/Stack.h
index 94e987b7b9..06ca54a576 100644
--- a/moses2/defer/CubePruningCardinalStack/Stack.h
+++ b/moses2/defer/CubePruningCardinalStack/Stack.h
@@ -6,7 +6,6 @@
  */
 #pragma once
 #include <boost/unordered_map.hpp>
-#include <boost/unordered_set.hpp>
 #include <deque>
 #include "../Hypothesis.h"
 #include "../../TypeDef.h"
@@ -29,7 +28,7 @@ typedef Vector<const Hypothesis*>  Hypotheses;
 class Stack
 {
 protected:
-  typedef boost::unordered_set<const Hypothesis*,
+  typedef std::unordered_set<const Hypothesis*,
           UnorderedComparer<Hypothesis>,
           UnorderedComparer<Hypothesis>
           > _HCType;
diff --git a/moses2/defer/CubePruningPerBitmap/Misc.h b/moses2/defer/CubePruningPerBitmap/Misc.h
index 3fa22f9a6b..6a17e66a32 100644
--- a/moses2/defer/CubePruningPerBitmap/Misc.h
+++ b/moses2/defer/CubePruningPerBitmap/Misc.h
@@ -7,7 +7,6 @@
 #pragma once
 #include <boost/pool/pool_alloc.hpp>
 #include <boost/unordered_map.hpp>
-#include <boost/unordered_set.hpp>
 #include <vector>
 #include <queue>
 #include "../../legacy/Range.h"
@@ -72,7 +71,7 @@ class CubeEdge
           QueueItemOrderer> Queue;
 
   typedef std::pair<const CubeEdge*, int> SeenPositionItem;
-  typedef boost::unordered_set<SeenPositionItem,
+  typedef std::unordered_set<SeenPositionItem,
           boost::hash<SeenPositionItem>,
           std::equal_to<SeenPositionItem>
           > SeenPositions;
diff --git a/moses2/defer/CubePruningPerMiniStack/Misc.h b/moses2/defer/CubePruningPerMiniStack/Misc.h
index 511fd42f57..7b48e31bd2 100644
--- a/moses2/defer/CubePruningPerMiniStack/Misc.h
+++ b/moses2/defer/CubePruningPerMiniStack/Misc.h
@@ -7,7 +7,6 @@
 #pragma once
 #include <boost/pool/pool_alloc.hpp>
 #include <boost/unordered_map.hpp>
-#include <boost/unordered_set.hpp>
 #include <vector>
 #include <queue>
 #include "../../legacy/Range.h"
@@ -72,7 +71,7 @@ class CubeEdge
           QueueItemOrderer> Queue;
 
   typedef std::pair<const CubeEdge*, int> SeenPositionItem;
-  typedef boost::unordered_set<SeenPositionItem,
+  typedef std::unordered_set<SeenPositionItem,
           boost::hash<SeenPositionItem>,
           std::equal_to<SeenPositionItem>
           > SeenPositions;
diff --git a/moses2/legacy/Bitmaps.h b/moses2/legacy/Bitmaps.h
index aa0ea8f82e..f07318f933 100644
--- a/moses2/legacy/Bitmaps.h
+++ b/moses2/legacy/Bitmaps.h
@@ -1,6 +1,5 @@
 #pragma once
 
-#include <boost/unordered_set.hpp>
 #include <boost/unordered_map.hpp>
 #include <set>
 #include <stack>
diff --git a/moses2/legacy/FactorCollection.h b/moses2/legacy/FactorCollection.h
index 1b29dee699..fb6a646f41 100644
--- a/moses2/legacy/FactorCollection.h
+++ b/moses2/legacy/FactorCollection.h
@@ -31,7 +31,7 @@
 #endif
 
 #include "util/murmur_hash.hh"
-#include <boost/unordered_set.hpp>
+#include <unordered_set>
 
 #include <functional>
 #include <string>
@@ -82,7 +82,7 @@ class FactorCollection
       return left.in.GetString() == right.in.GetString();
     }
   };
-  typedef boost::unordered_set<FactorFriend, HashFactor, EqualsFactor> Set;
+  typedef std::unordered_set<FactorFriend, HashFactor, EqualsFactor> Set;
   Set m_set;
   Set m_setNonTerminal;