diff --git a/ChangeLog b/ChangeLog
index 18313c1..e96ec61 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2020-07-28  Alexei Podtelezhnikov  <apodtele@gmail.com>
+
+	Hide internal functions with SunPro.
+
+	* include/freetype/internal/compiler-macros.h
+	(FT_INTERNAL_FUNCTION_ATTRIBUTE) <__SUNPRO_C>: Define as __hidden.
+
 2020-07-28  Anuj Verma  <anujv@iitbhilai.ac.in>
 
 	Fix static compilation with Visual C.
diff --git a/include/freetype/internal/compiler-macros.h b/include/freetype/internal/compiler-macros.h
index 8ed3d11..f0002e5 100644
--- a/include/freetype/internal/compiler-macros.h
+++ b/include/freetype/internal/compiler-macros.h
@@ -115,6 +115,11 @@
 #define FT_INTERNAL_FUNCTION_ATTRIBUTE  \
           __attribute__(( visibility( "hidden" ) ))
 
+  /* Sun */
+#elif defined( __SUNPRO_C ) && __SUNPRO_C >= 0x550
+#define FT_INTERNAL_FUNCTION_ATTRIBUTE  __hidden
+#endif
+
 #else
 #define FT_INTERNAL_FUNCTION_ATTRIBUTE  /* empty */
 #endif