diff --git a/lib/argparser.hh b/lib/argparser.hh
index 2218217..d667669 100644
--- a/lib/argparser.hh
+++ b/lib/argparser.hh
@@ -1,7 +1,6 @@
 // This Source Code Form is licensed MPL-2.0: http://mozilla.org/MPL/2.0
 
-#ifndef LIQUIDSFZ_ARGPARSER_HH
-#define LIQUIDSFZ_ARGPARSER_HH
+#pragma once
 
 #include <vector>
 #include <string>
@@ -25,5 +24,3 @@ public:
 };
 
 }
-
-#endif /* LIQUIDSFZ_ARGPARSER_HH */
diff --git a/lib/curve.hh b/lib/curve.hh
index e4b23de..311aec8 100644
--- a/lib/curve.hh
+++ b/lib/curve.hh
@@ -1,7 +1,6 @@
 // This Source Code Form is licensed MPL-2.0: http://mozilla.org/MPL/2.0
 
-#ifndef LIQUIDSFZ_CURVE_HH
-#define LIQUIDSFZ_CURVE_HH
+#pragma once
 
 #include <vector>
 #include <map>
@@ -92,5 +91,3 @@ public:
 };
 
 }
-
-#endif /* LIQUIDSFZ_CURVE_HH */
diff --git a/lib/envelope.hh b/lib/envelope.hh
index 7b1a336..9659cb0 100644
--- a/lib/envelope.hh
+++ b/lib/envelope.hh
@@ -1,7 +1,6 @@
 // This Source Code Form is licensed MPL-2.0: http://mozilla.org/MPL/2.0
 
-#ifndef LIQUIDSFZ_ENVELOPE_HH
-#define LIQUIDSFZ_ENVELOPE_HH
+#pragma once
 
 #include "loader.hh"
 
@@ -249,5 +248,3 @@ public:
 };
 
 }
-
-#endif /* LIQUIDSFZ_ENVELOPE_HH */
diff --git a/lib/filter.hh b/lib/filter.hh
index 0f4cf8d..59f0492 100644
--- a/lib/filter.hh
+++ b/lib/filter.hh
@@ -1,7 +1,6 @@
 // This Source Code Form is licensed MPL-2.0: http://mozilla.org/MPL/2.0
 
-#ifndef LIQUIDSFZ_FILTER_HH
-#define LIQUIDSFZ_FILTER_HH
+#pragma once
 
 #include <cmath>
 #include <string>
@@ -405,5 +404,3 @@ public:
 };
 
 }
-
-#endif /* LIQUIDSFZ_FILTER_HH */
diff --git a/lib/hydrogenimport.hh b/lib/hydrogenimport.hh
index 3687811..9a6fa68 100644
--- a/lib/hydrogenimport.hh
+++ b/lib/hydrogenimport.hh
@@ -1,7 +1,6 @@
 // This Source Code Form is licensed MPL-2.0: http://mozilla.org/MPL/2.0
 
-#ifndef LIQUIDSFZ_HYDROGEN_HH
-#define LIQUIDSFZ_HYDROGEN_HH
+#pragma once
 
 #include <string>
 
@@ -40,5 +39,3 @@ public:
 };
 
 }
-
-#endif /* LIQUIDSFZ_HYDROGEN_HH */
diff --git a/lib/lfogen.hh b/lib/lfogen.hh
index eeb7695..fa43405 100644
--- a/lib/lfogen.hh
+++ b/lib/lfogen.hh
@@ -1,7 +1,6 @@
 // This Source Code Form is licensed MPL-2.0: http://mozilla.org/MPL/2.0
 
-#ifndef LIQUIDSFZ_LFOGEN_HH
-#define LIQUIDSFZ_LFOGEN_HH
+#pragma once
 
 #include "utils.hh"
 
@@ -101,5 +100,3 @@ public:
 };
 
 }
-
-#endif /* LIQUIDSFZ_LFOGEN_HH */
diff --git a/lib/liquidsfz.hh b/lib/liquidsfz.hh
index 25c4106..50ded87 100644
--- a/lib/liquidsfz.hh
+++ b/lib/liquidsfz.hh
@@ -1,7 +1,6 @@
 // This Source Code Form is licensed MPL-2.0: http://mozilla.org/MPL/2.0
 
-#ifndef LIQUIDSFZ_LIQUIDSFZ_HH
-#define LIQUIDSFZ_LIQUIDSFZ_HH
+#pragma once
 
 #include <memory>
 #include <functional>
@@ -628,4 +627,3 @@ messages will break realtime capabilty.
 */
 
 }
-#endif
diff --git a/lib/loader.hh b/lib/loader.hh
index b67bdc9..2ac4a52 100644
--- a/lib/loader.hh
+++ b/lib/loader.hh
@@ -1,7 +1,6 @@
 // This Source Code Form is licensed MPL-2.0: http://mozilla.org/MPL/2.0
 
-#ifndef LIQUIDSFZ_LOADER_HH
-#define LIQUIDSFZ_LOADER_HH
+#pragma once
 
 #include <string>
 #include <set>
@@ -512,5 +511,3 @@ public:
 };
 
 }
-
-#endif /* LIQUIDSFZ_LOADER_HH */
diff --git a/lib/log.hh b/lib/log.hh
index 58e609f..0767f3b 100644
--- a/lib/log.hh
+++ b/lib/log.hh
@@ -1,5 +1,7 @@
 // This Source Code Form is licensed MPL-2.0: http://mozilla.org/MPL/2.0
 
+#pragma once
+
 #include "utils.hh"
 
 #include <string>
diff --git a/lib/midnam.hh b/lib/midnam.hh
index ece2e98..eaa3ec6 100644
--- a/lib/midnam.hh
+++ b/lib/midnam.hh
@@ -1,5 +1,7 @@
 // This Source Code Form is licensed MPL-2.0: http://mozilla.org/MPL/2.0
 
+#pragma once
+
 #include "synth.hh"
 
 namespace LiquidSFZInternal
diff --git a/lib/samplecache.hh b/lib/samplecache.hh
index e86d876..3283129 100644
--- a/lib/samplecache.hh
+++ b/lib/samplecache.hh
@@ -1,7 +1,6 @@
 // This Source Code Form is licensed MPL-2.0: http://mozilla.org/MPL/2.0
 
-#ifndef LIQUIDSFZ_SAMPLECACHE_HH
-#define LIQUIDSFZ_SAMPLECACHE_HH
+#pragma once
 
 #include <vector>
 #include <functional>
@@ -483,5 +482,3 @@ Sample::end_playback()
 }
 
 }
-
-#endif /* LIQUIDSFZ_SAMPLECACHE_HH */
diff --git a/lib/sfpool.hh b/lib/sfpool.hh
index 2bb5a43..f64a922 100644
--- a/lib/sfpool.hh
+++ b/lib/sfpool.hh
@@ -1,7 +1,6 @@
 // This Source Code Form is licensed MPL-2.0: http://mozilla.org/MPL/2.0
 
-#ifndef LIQUIDSFZ_SFPOOL_HH
-#define LIQUIDSFZ_SFPOOL_HH
+#pragma once
 
 #include <sndfile.h>
 
@@ -63,5 +62,3 @@ public:
 };
 
 }
-
-#endif /* LIQUIDSFZ_SFPOOL_HH */
diff --git a/lib/synth.hh b/lib/synth.hh
index ad9fa5b..59f87e7 100644
--- a/lib/synth.hh
+++ b/lib/synth.hh
@@ -1,7 +1,6 @@
 // This Source Code Form is licensed MPL-2.0: http://mozilla.org/MPL/2.0
 
-#ifndef LIQUIDSFZ_SYNTH_HH
-#define LIQUIDSFZ_SYNTH_HH
+#pragma once
 
 #include <random>
 #include <algorithm>
@@ -708,5 +707,3 @@ public:
 };
 
 }
-
-#endif /* LIQUIDSFZ_SYNTH_HH */
diff --git a/lib/upsample.hh b/lib/upsample.hh
index a6c6a71..b0d4cde 100644
--- a/lib/upsample.hh
+++ b/lib/upsample.hh
@@ -1,7 +1,6 @@
 // This Source Code Form is licensed MPL-2.0: http://mozilla.org/MPL/2.0
 
-#ifndef LIQUIDSFZ_UPSAMPLE_HH
-#define LIQUIDSFZ_UPSAMPLE_HH
+#pragma once
 
 namespace LiquidSFZInternal
 {
@@ -89,5 +88,3 @@ upsample (const float *in, float *out)
 }
 
 }
-
-#endif /* LIQUIDSFZ_UPSAMPLE_HH */
diff --git a/lib/utils.hh b/lib/utils.hh
index b1bf5e5..c8cd3e3 100644
--- a/lib/utils.hh
+++ b/lib/utils.hh
@@ -1,7 +1,6 @@
 // This Source Code Form is licensed MPL-2.0: http://mozilla.org/MPL/2.0
 
-#ifndef LIQUIDSFZ_UTILS_HH
-#define LIQUIDSFZ_UTILS_HH
+#pragma once
 
 #include <cstring>
 
@@ -134,5 +133,3 @@ public:
 };
 
 }
-
-#endif /* LIQUIDSFZ_UTILS_HH */
diff --git a/lib/voice.hh b/lib/voice.hh
index 328bb95..d778d69 100644
--- a/lib/voice.hh
+++ b/lib/voice.hh
@@ -1,7 +1,6 @@
 // This Source Code Form is licensed MPL-2.0: http://mozilla.org/MPL/2.0
 
-#ifndef LIQUIDSFZ_VOICE_HH
-#define LIQUIDSFZ_VOICE_HH
+#pragma once
 
 #include "envelope.hh"
 #include "filter.hh"
@@ -164,5 +163,3 @@ public:
 };
 
 }
-
-#endif /* LIQUIDSFZ_VOICE_HH */