diff --git a/README.md b/README.md
index cab257f..f928346 100644
--- a/README.md
+++ b/README.md
@@ -116,6 +116,7 @@ io.Seeker
 io.Writer
 io.WriterAt
 
+Chmod(mode os.FileMode) : error
 Name() : string
 Readdir(count int) : []os.FileInfo, error
 Readdirnames(n int) : []string, error
diff --git a/afero.go b/afero.go
index 469ff7d..fdb2996 100644
--- a/afero.go
+++ b/afero.go
@@ -42,6 +42,7 @@ type File interface {
 	io.Writer
 	io.WriterAt
 
+	Chmod(mode os.FileMode) error
 	Name() string
 	Readdir(count int) ([]os.FileInfo, error)
 	Readdirnames(n int) ([]string, error)
diff --git a/gcsfs/file.go b/gcsfs/file.go
index f916bd2..c549d23 100644
--- a/gcsfs/file.go
+++ b/gcsfs/file.go
@@ -18,6 +18,7 @@ package gcsfs
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"log"
@@ -175,6 +176,10 @@ func (o *GcsFile) WriteAt(b []byte, off int64) (n int, err error) {
 	return written, err
 }
 
+func (o *GcsFile) Chmod(mode os.FileMode) error {
+	return errors.New("method Chmod is not implemented in GCS")
+}
+
 func (o *GcsFile) Name() string {
 	return filepath.FromSlash(o.resource.name)
 }
diff --git a/iofs.go b/iofs.go
index c803455..b948308 100644
--- a/iofs.go
+++ b/iofs.go
@@ -203,6 +203,10 @@ type fromIOFSFile struct {
 	name string
 }
 
+func (f fromIOFSFile) Chmod(mode os.FileMode) error {
+	return notImplemented("chmod", f.name)
+}
+
 func (f fromIOFSFile) ReadAt(p []byte, off int64) (n int, err error) {
 	readerAt, ok := f.File.(io.ReaderAt)
 	if !ok {
diff --git a/mem/file.go b/mem/file.go
index 5ef8b6a..ffc58c6 100644
--- a/mem/file.go
+++ b/mem/file.go
@@ -25,7 +25,11 @@ import (
 	"time"
 )
 
-const FilePathSeparator = string(filepath.Separator)
+const (
+	FilePathSeparator = string(filepath.Separator)
+
+	chmodBits = os.ModePerm | os.ModeSetuid | os.ModeSetgid | os.ModeSticky // Only a subset of bits are allowed to be changed. Documented under os.Chmod()
+)
 
 type File struct {
 	// atomic requires 64-bit alignment for struct field access
@@ -67,11 +71,20 @@ func (d *FileData) Name() string {
 }
 
 func CreateFile(name string) *FileData {
-	return &FileData{name: name, mode: os.ModeTemporary, modtime: time.Now()}
+	return &FileData{
+		name:    name,
+		modtime: time.Now(),
+	}
 }
 
 func CreateDir(name string) *FileData {
-	return &FileData{name: name, memDir: &DirMap{}, dir: true, modtime: time.Now()}
+	return &FileData{
+		name:    name,
+		mode:    os.ModeDir,
+		memDir:  &DirMap{},
+		dir:     true,
+		modtime: time.Now(),
+	}
 }
 
 func ChangeFileName(f *FileData, newname string) {
@@ -80,9 +93,9 @@ func ChangeFileName(f *FileData, newname string) {
 	f.Unlock()
 }
 
-func SetMode(f *FileData, mode os.FileMode) {
+func Chmod(f *FileData, mode os.FileMode) {
 	f.Lock()
-	f.mode = mode
+	f.mode = (f.mode & ^chmodBits) | (mode & chmodBits)
 	f.Unlock()
 }
 
@@ -131,6 +144,11 @@ func (f *File) Close() error {
 	return nil
 }
 
+func (f *File) Chmod(mode os.FileMode) error {
+	Chmod(f.fileData, mode)
+	return nil
+}
+
 func (f *File) Name() string {
 	return f.fileData.Name()
 }
diff --git a/mem/file_test.go b/mem/file_test.go
index 998a5d0..59408a4 100644
--- a/mem/file_test.go
+++ b/mem/file_test.go
@@ -81,13 +81,13 @@ func TestFileDataModeRace(t *testing.T) {
 		t.Errorf("Failed to read correct value, was %v", s.Mode())
 	}
 
-	SetMode(&d, someOtherMode)
+	Chmod(&d, someOtherMode)
 	if s.Mode() != someOtherMode {
 		t.Errorf("Failed to set Mode, was %v", s.Mode())
 	}
 
 	go func() {
-		SetMode(&d, someMode)
+		Chmod(&d, someMode)
 	}()
 
 	if s.Mode() != someMode && s.Mode() != someOtherMode {
diff --git a/memmap.go b/memmap.go
index ea0798d..60c5537 100644
--- a/memmap.go
+++ b/memmap.go
@@ -25,8 +25,6 @@ import (
 	"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()
-
 type MemMapFs struct {
 	mu   sync.RWMutex
 	data map[string]*mem.FileData
@@ -43,7 +41,7 @@ func (m *MemMapFs) getData() map[string]*mem.FileData {
 		// Root should always exist, right?
 		// TODO: what about windows?
 		root := mem.CreateDir(FilePathSeparator)
-		mem.SetMode(root, os.ModeDir|0755)
+		mem.Chmod(root, 0755)
 		m.data[FilePathSeparator] = root
 	})
 	return m.data
@@ -123,7 +121,7 @@ func (m *MemMapFs) lockfreeMkdir(name string, perm os.FileMode) error {
 		}
 	} else {
 		item := mem.CreateDir(name)
-		mem.SetMode(item, os.ModeDir|perm)
+		mem.Chmod(item, perm)
 		m.getData()[name] = item
 		m.registerWithParent(item, perm)
 	}
@@ -131,7 +129,6 @@ func (m *MemMapFs) lockfreeMkdir(name string, perm os.FileMode) error {
 }
 
 func (m *MemMapFs) Mkdir(name string, perm os.FileMode) error {
-	perm &= chmodBits
 	name = normalizePath(name)
 
 	m.mu.RLock()
@@ -143,12 +140,12 @@ func (m *MemMapFs) Mkdir(name string, perm os.FileMode) error {
 
 	m.mu.Lock()
 	item := mem.CreateDir(name)
-	mem.SetMode(item, os.ModeDir|perm)
+	mem.Chmod(item, perm)
 	m.getData()[name] = item
 	m.registerWithParent(item, perm)
 	m.mu.Unlock()
 
-	return m.setFileMode(name, perm|os.ModeDir)
+	return nil
 }
 
 func (m *MemMapFs) MkdirAll(path string, perm os.FileMode) error {
@@ -215,7 +212,6 @@ func (m *MemMapFs) lockfreeOpen(name string) (*mem.FileData, error) {
 }
 
 func (m *MemMapFs) OpenFile(name string, flag int, perm os.FileMode) (File, error) {
-	perm &= chmodBits
 	chmod := false
 	file, err := m.openWrite(name)
 	if err == nil && (flag&os.O_EXCL > 0) {
@@ -246,7 +242,7 @@ func (m *MemMapFs) OpenFile(name string, flag int, perm os.FileMode) (File, erro
 		}
 	}
 	if chmod {
-		return file, m.setFileMode(name, perm)
+		m.Chmod(name, perm)
 	}
 	return file, nil
 }
@@ -331,45 +327,30 @@ func (m *MemMapFs) Stat(name string) (os.FileInfo, error) {
 	return fi, nil
 }
 
-func (m *MemMapFs) Chmod(name string, mode os.FileMode) error {
-	mode &= chmodBits
-
-	m.mu.RLock()
-	f, ok := m.getData()[name]
-	m.mu.RUnlock()
-	if !ok {
-		return &os.PathError{Op: "chmod", Path: name, Err: ErrFileNotFound}
-	}
-	prevOtherBits := mem.GetFileInfo(f).Mode() & ^chmodBits
-
-	mode = prevOtherBits | mode
-	return m.setFileMode(name, mode)
-}
-
-func (m *MemMapFs) setFileMode(name string, mode os.FileMode) error {
+func (m *MemMapFs) getFileData(name string) *mem.FileData {
 	name = normalizePath(name)
 
 	m.mu.RLock()
-	f, ok := m.getData()[name]
+	f := m.getData()[name]
 	m.mu.RUnlock()
-	if !ok {
+
+	return f
+}
+
+func (m *MemMapFs) Chmod(name string, mode os.FileMode) error {
+	f := m.getFileData(name)
+	if f == nil {
 		return &os.PathError{Op: "chmod", Path: name, Err: ErrFileNotFound}
 	}
 
-	m.mu.Lock()
-	mem.SetMode(f, mode)
-	m.mu.Unlock()
+	mem.Chmod(f, mode)
 
 	return nil
 }
 
 func (m *MemMapFs) Chown(name string, uid, gid int) error {
-	name = normalizePath(name)
-
-	m.mu.RLock()
-	f, ok := m.getData()[name]
-	m.mu.RUnlock()
-	if !ok {
+	f := m.getFileData(name)
+	if f == nil {
 		return &os.PathError{Op: "chown", Path: name, Err: ErrFileNotFound}
 	}
 
@@ -380,18 +361,12 @@ func (m *MemMapFs) Chown(name string, uid, gid int) error {
 }
 
 func (m *MemMapFs) Chtimes(name string, atime time.Time, mtime time.Time) error {
-	name = normalizePath(name)
-
-	m.mu.RLock()
-	f, ok := m.getData()[name]
-	m.mu.RUnlock()
-	if !ok {
+	f := m.getFileData(name)
+	if f == nil {
 		return &os.PathError{Op: "chtimes", Path: name, Err: ErrFileNotFound}
 	}
 
-	m.mu.Lock()
 	mem.SetModTime(f, mtime)
-	m.mu.Unlock()
 
 	return nil
 }
diff --git a/memmap_test.go b/memmap_test.go
index 881a61b..613f402 100644
--- a/memmap_test.go
+++ b/memmap_test.go
@@ -614,7 +614,7 @@ func TestMemFsChmod(t *testing.T) {
 		t.Fatal("mkdir failed to create a directory: mode =", info.Mode())
 	}
 
-	err = fs.Chmod(file, 0)
+	err = fs.Chmod(file, os.ModeTemporary|0355)
 	if err != nil {
 		t.Error("Failed to run chmod:", err)
 	}
@@ -623,9 +623,29 @@ func TestMemFsChmod(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if info.Mode().String() != "d---------" {
-		t.Error("chmod should not change file type. New mode =", info.Mode())
+	if info.Mode().String() != "d-wxr-xr-x" {
+		t.Error("incorrect file mode after chmod:", info.Mode())
 	}
+
+	f, err := fs.Open(file)
+	if err != nil {
+		t.Error("failed to open file:", err)
+	}
+
+	err = f.Chmod(os.ModeNamedPipe | 0744)
+	if err != nil {
+		t.Error("Failed to run chmod:", err)
+	}
+
+	info, err = fs.Stat(file)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if info.Mode().String() != "drwxr--r--" {
+		t.Error("incorrect file mode after chmod:", info.Mode())
+	}
+
+	f.Close()
 }
 
 // can't use Mkdir to get around which permissions we're allowed to set
diff --git a/regexpfs.go b/regexpfs.go
index ac359c6..d43bf93 100644
--- a/regexpfs.go
+++ b/regexpfs.go
@@ -178,6 +178,10 @@ func (f *RegexpFile) WriteAt(s []byte, o int64) (int, error) {
 	return f.f.WriteAt(s, o)
 }
 
+func (f *RegexpFile) Chmod(mode os.FileMode) error {
+	return f.f.Chmod(mode)
+}
+
 func (f *RegexpFile) Name() string {
 	return f.f.Name()
 }
diff --git a/sftpfs/file.go b/sftpfs/file.go
index eef14e3..979dce3 100644
--- a/sftpfs/file.go
+++ b/sftpfs/file.go
@@ -44,6 +44,10 @@ func (f *File) Close() error {
 	return f.fd.Close()
 }
 
+func (f *File) Chmod(mode os.FileMode) error {
+	return f.fd.Chmod(mode)
+}
+
 func (f *File) Name() string {
 	return f.fd.Name()
 }
diff --git a/tarfs/file.go b/tarfs/file.go
index e1d63ed..6e09f06 100644
--- a/tarfs/file.go
+++ b/tarfs/file.go
@@ -71,6 +71,10 @@ func (f *File) Write(p []byte) (n int, err error) { return 0, syscall.EROFS }
 
 func (f *File) WriteAt(p []byte, off int64) (n int, err error) { return 0, syscall.EROFS }
 
+func (f *File) Chmod(mode os.FileMode) error {
+	return syscall.EROFS
+}
+
 func (f *File) Name() string {
 	return filepath.Join(splitpath(f.h.Name))
 }
diff --git a/unionFile.go b/unionFile.go
index 34f99a4..8dbfb6d 100644
--- a/unionFile.go
+++ b/unionFile.go
@@ -41,6 +41,20 @@ func (f *UnionFile) Close() error {
 	return BADFD
 }
 
+func (f *UnionFile) Chmod(mode os.FileMode) error {
+	if f.Layer != nil {
+		err := f.Layer.Chmod(mode)
+		if err == nil && f.Base != nil {
+			err = f.Base.Chmod(mode)
+		}
+		return err
+	}
+	if f.Base != nil {
+		return f.Base.Chmod(mode)
+	}
+	return BADFD
+}
+
 func (f *UnionFile) Read(s []byte) (int, error) {
 	if f.Layer != nil {
 		n, err := f.Layer.Read(s)
diff --git a/zipfs/file.go b/zipfs/file.go
index 355f5f4..e3eb90e 100644
--- a/zipfs/file.go
+++ b/zipfs/file.go
@@ -104,6 +104,10 @@ func (f *File) Write(p []byte) (n int, err error) { return 0, syscall.EPERM }
 
 func (f *File) WriteAt(p []byte, off int64) (n int, err error) { return 0, syscall.EPERM }
 
+func (f *File) Chmod(mode os.FileMode) error {
+	return syscall.EPERM
+}
+
 func (f *File) Name() string {
 	if f.zipfile == nil {
 		return string(filepath.Separator)