diff --git a/src/cairo-unicode.c b/src/cairo-unicode.c
index 2b224a3ab..18b9143d9 100644
--- a/src/cairo-unicode.c
+++ b/src/cairo-unicode.c
@@ -258,6 +258,7 @@ _cairo_utf8_to_ucs4 (const unsigned char *str,
     return CAIRO_STATUS_SUCCESS;
 }
 
+#if CAIRO_HAS_UTF8_TO_UTF16
 /**
  * _cairo_utf8_to_utf16:
  * @str: an UTF-8 string
@@ -333,3 +334,4 @@ _cairo_utf8_to_utf16 (const unsigned char *str,
 
     return CAIRO_STATUS_SUCCESS;
 }
+#endif
diff --git a/src/cairoint.h b/src/cairoint.h
index 5924ab3d3..4f8213aa8 100644
--- a/src/cairoint.h
+++ b/src/cairoint.h
@@ -2311,11 +2311,16 @@ _cairo_utf8_to_ucs4 (const unsigned char *str,
 		     uint32_t	        **result,
 		     int		 *items_written);
 
+#if CAIRO_HAS_WIN32_FONT+0 || CAIRO_HAS_ATSUI_FONT+0
+# define CAIRO_HAS_UTF8_TO_UTF16 1
+#endif
+#if CAIRO_HAS_UTF8_TO_UTF16
 cairo_private cairo_status_t
 _cairo_utf8_to_utf16 (const unsigned char *str,
 		      int		   len,
 		      uint16_t		 **result,
 		      int		  *items_written);
+#endif
 
 cairo_private cairo_status_t
 _cairo_error (cairo_status_t status);