diff --git a/sassutils/builder.py b/sassutils/builder.py
index 3390f45e..3bb72958 100644
--- a/sassutils/builder.py
+++ b/sassutils/builder.py
@@ -22,7 +22,7 @@
 
 #: (:class:`re.RegexObject`) The regular expression pattern which matches to
 #: filenames of supported :const:`SUFFIXES`.
-SUFFIX_PATTERN = re.compile('[.](' + '|'.join(map(re.escape, SUFFIXES)) + ')$')
+SUFFIX_PATTERN = re.compile('[.](' + '|'.join(map(re.escape, sorted(SUFFIXES))) + ')$')
 
 
 def build_directory(