diff --git a/src/CabalFmt/Fields/SourceFiles.hs b/src/CabalFmt/Fields/SourceFiles.hs
index a387640..cf0f005 100644
--- a/src/CabalFmt/Fields/SourceFiles.hs
+++ b/src/CabalFmt/Fields/SourceFiles.hs
@@ -7,7 +7,9 @@ module CabalFmt.Fields.SourceFiles (
     fileFields,
     ) where
 
-import System.FilePath.Posix (splitDirectories)
+-- Make sure we explicitly use Posix's splitDirectories
+-- when parsing glob syntax since only `/` is valid, and not '\\'
+import qualified System.FilePath.Posix     as Posix (splitDirectories)
 
 import qualified Distribution.FieldGrammar as C
 import qualified Distribution.Fields       as C
@@ -46,7 +48,7 @@ pretty :: [FilePath] -> PP.Doc
 pretty
     = PP.vcat . map C.showFilePath
     . nub
-    . sortBy (cmp `on` map strToLower . splitDirectories)
+    . sortBy (cmp `on` map strToLower . Posix.splitDirectories)
   where
     cmp a b = case dropCommonPrefix a b of
         ([], [])  -> EQ
diff --git a/src/CabalFmt/Glob.hs b/src/CabalFmt/Glob.hs
index d368991..e8d04f1 100644
--- a/src/CabalFmt/Glob.hs
+++ b/src/CabalFmt/Glob.hs
@@ -2,7 +2,9 @@ module CabalFmt.Glob where
 
 import Data.List             (isInfixOf)
 import Data.List.NonEmpty    (NonEmpty (..))
-import System.FilePath.Posix (splitDirectories)
+-- Make sure we explicitly use Posix's splitDirectories
+-- when parsing glob syntax since only `/` is valid, and not '\\'
+import qualified System.FilePath.Posix as Posix (splitDirectories)
 
 import CabalFmt.Prelude
 
@@ -27,7 +29,7 @@ data GlobChar
 -- [False,False,True,True]
 --
 match :: Glob -> FilePath -> Bool
-match (Glob g1 gs0) fp = go0 (splitDirectories fp) where
+match (Glob g1 gs0) fp = go0 (Posix.splitDirectories fp) where
     go0 []     = False
     go0 (p:ps) = if p == g1 then go ps gs0 else False
 
@@ -47,7 +49,7 @@ match (Glob g1 gs0) fp = go0 (splitDirectories fp) where
     matches (x:xs) (GlobChar c : cs) = if x == c then matches xs cs else False
 
 parseGlob :: String -> Either String Glob
-parseGlob input = case splitDirectories input of
+parseGlob input = case Posix.splitDirectories input of
     []     -> Left "empty path"
     (x:xs) -> do
         p <- parseFirstPiece x