diff --git a/memmap.go b/memmap.go
index c139aa15..d276a301 100644
--- a/memmap.go
+++ b/memmap.go
@@ -15,14 +15,14 @@ package afero
 
 import (
 	"fmt"
+	"github.com/spf13/afero/mem"
 	"log"
 	"os"
 	"path/filepath"
+	"sort"
 	"strings"
 	"sync"
 	"time"
-
-	"github.com/spf13/afero/mem"
 )
 
 const chmodBits = os.ModePerm | os.ModeSetuid | os.ModeSetgid | os.ModeSticky // Only a subset of bits are allowed to be changed. Documented under os.Chmod()
@@ -96,6 +96,12 @@ func (m *MemMapFs) findDescendants(name string) []*mem.FileData {
 		}
 	}
 
+	sort.Slice(descendants, func(i, j int) bool {
+		cur := len(strings.Split(descendants[i].Name(), FilePathSeparator))
+		next := len(strings.Split(descendants[j].Name(), FilePathSeparator))
+		return cur < next
+	})
+
 	return descendants
 }
 
@@ -320,14 +326,15 @@ func (m *MemMapFs) Rename(oldName, newName string) error {
 			return err
 		}
 
+		fileData := m.getData()[oldName]
+		mem.ChangeFileName(fileData, newName)
+		m.getData()[newName] = fileData
+
 		err = m.renameDescendants(oldName, newName)
 		if err != nil {
 			return err
 		}
 
-		fileData := m.getData()[oldName]
-		mem.ChangeFileName(fileData, newName)
-		m.getData()[newName] = fileData
 		delete(m.getData(), oldName)
 
 		m.registerWithParent(fileData, 0)