diff --git a/poly2tri/common/dll_symbol.h b/poly2tri/common/dll_symbol.h
index 92c50cb..bf5d202 100644
--- a/poly2tri/common/dll_symbol.h
+++ b/poly2tri/common/dll_symbol.h
@@ -29,8 +29,7 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef DLL_SYMBOL_H
-#define DLL_SYMBOL_H
+#pragma once
 
 #if defined(_WIN32)
 #  define P2T_COMPILER_DLLEXPORT __declspec(dllexport)
@@ -52,5 +51,3 @@
 #    define P2T_DLL_SYMBOL P2T_COMPILER_DLLIMPORT
 #  endif
 #endif
-
-#endif
diff --git a/poly2tri/common/shapes.h b/poly2tri/common/shapes.h
index 489558d..d78aa87 100644
--- a/poly2tri/common/shapes.h
+++ b/poly2tri/common/shapes.h
@@ -29,9 +29,7 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-// Include guard
-#ifndef SHAPES_H
-#define SHAPES_H
+#pragma once
 
 #include "dll_symbol.h"
 
@@ -329,5 +327,3 @@ inline void Triangle::IsInterior(bool b)
 P2T_DLL_SYMBOL bool IsDelaunay(const std::vector<p2t::Triangle*>&);
 
 }
-
-#endif
diff --git a/poly2tri/common/utils.h b/poly2tri/common/utils.h
index 6a20a00..c9f1c23 100644
--- a/poly2tri/common/utils.h
+++ b/poly2tri/common/utils.h
@@ -29,8 +29,7 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef UTILS_H
-#define UTILS_H
+#pragma once
 
 // Otherwise #defines like M_PI are undeclared under Visual Studio
 #define _USE_MATH_DEFINES
@@ -129,5 +128,3 @@ bool InScanArea(const Point& pa, const Point& pb, const Point& pc, const Point&
 }
 
 }
-
-#endif
diff --git a/poly2tri/poly2tri.h b/poly2tri/poly2tri.h
index c959d13..3d40373 100644
--- a/poly2tri/poly2tri.h
+++ b/poly2tri/poly2tri.h
@@ -29,10 +29,7 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef POLY2TRI_H
-#define POLY2TRI_H
+#pragma once
 
 #include "common/shapes.h"
 #include "sweep/cdt.h"
-
-#endif
diff --git a/poly2tri/sweep/advancing_front.h b/poly2tri/sweep/advancing_front.h
index 3de0708..ffd3fe7 100644
--- a/poly2tri/sweep/advancing_front.h
+++ b/poly2tri/sweep/advancing_front.h
@@ -29,8 +29,7 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef ADVANCED_FRONT_H
-#define ADVANCED_FRONT_H
+#pragma once
 
 #include "../common/shapes.h"
 
@@ -114,5 +113,3 @@ inline void AdvancingFront::set_search(Node* node)
 }
 
 }
-
-#endif
diff --git a/poly2tri/sweep/cdt.h b/poly2tri/sweep/cdt.h
index 7e3a45a..7c54ea9 100644
--- a/poly2tri/sweep/cdt.h
+++ b/poly2tri/sweep/cdt.h
@@ -29,8 +29,7 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef CDT_H
-#define CDT_H
+#pragma once
 
 #include "advancing_front.h"
 #include "sweep_context.h"
@@ -103,5 +102,3 @@ public:
 };
 
 }
-
-#endif
diff --git a/poly2tri/sweep/sweep.h b/poly2tri/sweep/sweep.h
index 895b0e8..ec3b4b8 100644
--- a/poly2tri/sweep/sweep.h
+++ b/poly2tri/sweep/sweep.h
@@ -36,8 +36,7 @@
  * "FlipScan" Constrained Edge Algorithm invented by Thomas Åhlén, thahlen@gmail.com
  */
 
-#ifndef SWEEP_H
-#define SWEEP_H
+#pragma once
 
 #include <vector>
 
@@ -281,5 +280,3 @@ private:
 };
 
 }
-
-#endif
diff --git a/poly2tri/sweep/sweep_context.h b/poly2tri/sweep/sweep_context.h
index da62181..11d5739 100644
--- a/poly2tri/sweep/sweep_context.h
+++ b/poly2tri/sweep/sweep_context.h
@@ -29,8 +29,7 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef SWEEP_CONTEXT_H
-#define SWEEP_CONTEXT_H
+#pragma once
 
 #include <list>
 #include <vector>
@@ -183,5 +182,3 @@ inline Point* SweepContext::tail() const
 }
 
 }
-
-#endif