diff --git a/changelog b/changelog
--- a/changelog
+++ b/changelog
@@ -1,3 +1,10 @@
+texmath (0.12.3.1)
+
+  * MathML reader: don't allow mfenced attributes to inherit (#177).
+    When open and close attributes aren't given on an mfenced,
+    we should use defaults rather than inheriting these from a
+    parent mfenced.
+
 texmath (0.12.3)
 
   * TeX reader: implement logic to convert a Bin symbol to
diff --git a/src/Text/TeXMath/Readers/MathML.hs b/src/Text/TeXMath/Readers/MathML.hs
--- a/src/Text/TeXMath/Readers/MathML.hs
+++ b/src/Text/TeXMath/Readers/MathML.hs
@@ -472,17 +472,17 @@
 multiscripts :: Element -> MML Exp
 multiscripts e = do
   let (xs, pres) = break ((== "mprescripts") . name) (elChildren e)
-  let row' e' = if name e' == "none"
-                   then return $ EGrouped []
-                   else row e'
-  xs' <- mapM row' xs
+  let row'' e' = if name e' == "none"
+                    then return $ EGrouped []
+                    else row e'
+  xs' <- mapM row'' xs
   let base =
         case xs' of
           [x]       -> x
           [x,y]     -> ESub x y
           (x:y:z:_) -> ESubsup x y z
           []        -> EGrouped []
-  pres' <- mapM row' $ drop 1 pres
+  pres' <- mapM row'' $ drop 1 pres
   return $
     case pres' of
         (x:y:_) -> EGrouped [ESubsup (EGrouped []) x y, base]
@@ -598,7 +598,11 @@
 -- Kept as String for Text.XML.Light
 findAttrQ :: String -> Element -> MML (Maybe T.Text)
 findAttrQ s e = do
-  inherit <- asks (lookupAttrQ s . attrs)
+  inherit <- case (name e, s) of
+            ("mfenced", "open") -> return Nothing
+            ("mfenced", "close") -> return Nothing
+            ("mfenced", "separators") -> return Nothing
+            _ -> asks (lookupAttrQ s . attrs)
   return $ fmap T.pack $
     findAttr (QName s Nothing Nothing) e
       <|> inherit
diff --git a/texmath.cabal b/texmath.cabal
--- a/texmath.cabal
+++ b/texmath.cabal
@@ -1,5 +1,5 @@
 Name:                texmath
-Version:             0.12.3
+Version:             0.12.3.1
 Cabal-Version:       >= 1.10
 Build-type:          Simple
 Synopsis:            Conversion between formats used to represent mathematics.