diff --git a/src/hrtf/portable_endian.h b/src/hrtf/portable_endian.h
index 9cca60a..5fb4b55 100644
--- a/src/hrtf/portable_endian.h
+++ b/src/hrtf/portable_endian.h
@@ -13,7 +13,7 @@
 
 #endif
 
-#if defined(__linux__) || defined(__CYGWIN__)
+#if defined(__linux__) || defined(__CYGWIN__) || defined(__illumos__)
 
 #	include <endian.h>