diff --git a/WaiAppStatic/Storage/Embedded/Runtime.hs b/WaiAppStatic/Storage/Embedded/Runtime.hs
--- a/WaiAppStatic/Storage/Embedded/Runtime.hs
+++ b/WaiAppStatic/Storage/Embedded/Runtime.hs
@@ -19,6 +19,7 @@
 import Crypto.Hash.CryptoAPI (hash', MD5)
 import qualified Data.ByteString.Base64 as B64
 import WaiAppStatic.Storage.Filesystem (defaultFileServerSettings)
+import System.FilePath (pathSeparator)
 
 -- | Serve the list of path/content pairs directly from memory.
 embeddedSettings :: [(Prelude.FilePath, ByteString)] -> StaticSettings
@@ -63,7 +64,11 @@
     texts = map (\(x, y) -> (filter (not . T.null . fromPiece) $ toPieces' x, y)) fps
     toPieces' "" = []
     toPieces' x =
-        let (y, z) = break (== '/') x
+        -- See https://github.com/yesodweb/yesod/issues/626
+        --
+        -- We want to separate on the forward slash on *all* OSes, and on
+        -- Windows, also separate on a backslash.
+        let (y, z) = break (\c -> c == '/' || c == pathSeparator) x
          in unsafeToPiece (T.pack y) : toPieces' (drop 1 z)
 
     go :: [(Pieces, ByteString)] -> Embedded
diff --git a/wai-app-static.cabal b/wai-app-static.cabal
--- a/wai-app-static.cabal
+++ b/wai-app-static.cabal
@@ -1,5 +1,5 @@
 name:            wai-app-static
-version:         1.3.3
+version:         1.3.3.1
 license:         MIT
 license-file:    LICENSE
 author:          Michael Snoyman <michael@snoyman.com>
@@ -50,6 +50,7 @@
                    , unordered-containers      >= 0.2
                    , template-haskell          >= 2.7
                    , zlib                      >= 0.5
+                   , filepath
 
     exposed-modules: Network.Wai.Application.Static
                      WaiAppStatic.Storage.Filesystem