diff --git a/Lib/fontTools/feaLib/builder.py b/Lib/fontTools/feaLib/builder.py
index 36eed9514..02151620b 100644
--- a/Lib/fontTools/feaLib/builder.py
+++ b/Lib/fontTools/feaLib/builder.py
@@ -1338,7 +1338,7 @@ class Builder(object):
         # substitutions to be specified on target sequences that contain
         # glyph classes, the implementation software will enumerate
         # all specific glyph sequences if glyph classes are detected"
-        for g in sorted(itertools.product(*glyphs)):
+        for g in itertools.product(*glyphs):
             lookup.ligatures[g] = replacement
 
     # GSUB 5/6
diff --git a/Tests/feaLib/data/spec5d1.fea b/Tests/feaLib/data/spec5d1.fea
index cf7d76f70..a9a23f815 100644
--- a/Tests/feaLib/data/spec5d1.fea
+++ b/Tests/feaLib/data/spec5d1.fea
@@ -2,7 +2,7 @@
 # http://www.adobe.com/devnet/opentype/afdko/topic_feature_file_syntax.html
 
 feature F1 {
-  sub [one one.oldstyle] [slash fraction] [two two.oldstyle] by onehalf;
+  sub [one one.oldstyle] [fraction slash] [two two.oldstyle] by onehalf;
 } F1;
 
 # Since the OpenType specification does not allow ligature substitutions
@@ -12,12 +12,12 @@ feature F1 {
 # example produces an identical representation in the font as if all
 # the sequences were manually enumerated by the font editor:
 feature F2 {
-  sub one slash two by onehalf;
-  sub one.oldstyle slash two by onehalf;
   sub one fraction two by onehalf;
-  sub one.oldstyle fraction two by onehalf;
-  sub one slash two.oldstyle by onehalf;
-  sub one.oldstyle slash two.oldstyle by onehalf;
   sub one fraction two.oldstyle by onehalf;
+  sub one slash two by onehalf;
+  sub one slash two.oldstyle by onehalf;
+  sub one.oldstyle fraction two by onehalf;
   sub one.oldstyle fraction two.oldstyle by onehalf;
+  sub one.oldstyle slash two by onehalf;
+  sub one.oldstyle slash two.oldstyle by onehalf;
 } F2;
diff --git a/Tests/feaLib/data/spec5d1.ttx b/Tests/feaLib/data/spec5d1.ttx
index 79c0e8675..77dfc93b8 100644
--- a/Tests/feaLib/data/spec5d1.ttx
+++ b/Tests/feaLib/data/spec5d1.ttx
@@ -62,16 +62,16 @@
         <!-- SubTableCount=1 -->
         <LigatureSubst index="0">
           <LigatureSet glyph="one">
-            <Ligature components="slash,two" glyph="onehalf"/>
             <Ligature components="fraction,two" glyph="onehalf"/>
-            <Ligature components="slash,two.oldstyle" glyph="onehalf"/>
             <Ligature components="fraction,two.oldstyle" glyph="onehalf"/>
+            <Ligature components="slash,two" glyph="onehalf"/>
+            <Ligature components="slash,two.oldstyle" glyph="onehalf"/>
           </LigatureSet>
           <LigatureSet glyph="one.oldstyle">
-            <Ligature components="slash,two" glyph="onehalf"/>
             <Ligature components="fraction,two" glyph="onehalf"/>
-            <Ligature components="slash,two.oldstyle" glyph="onehalf"/>
             <Ligature components="fraction,two.oldstyle" glyph="onehalf"/>
+            <Ligature components="slash,two" glyph="onehalf"/>
+            <Ligature components="slash,two.oldstyle" glyph="onehalf"/>
           </LigatureSet>
         </LigatureSubst>
       </Lookup>