diff --git a/builder/virtualbox/builder.go b/builder/virtualbox/builder.go
index 02bf0d727..6aa8da108 100644
--- a/builder/virtualbox/builder.go
+++ b/builder/virtualbox/builder.go
@@ -16,6 +16,14 @@ import (
 
 const BuilderId = "mitchellh.virtualbox"
 
+// These are the different valid mode values for "guest_additions_mode" which
+// determine how guest additions are delivered to the guest.
+const (
+	GuestAdditionsModeDisable string = "disable"
+	GuestAdditionsModeAttach         = "attach"
+	GuestAdditionsModeUpload         = "upload"
+)
+
 type Builder struct {
 	config config
 	runner multistep.Runner
@@ -28,7 +36,7 @@ type config struct {
 	DiskSize             uint       `mapstructure:"disk_size"`
 	FloppyFiles          []string   `mapstructure:"floppy_files"`
 	Format               string     `mapstructure:"format"`
-	GuestAdditionsAttach bool       `mapstructure:"guest_additions_attach"`
+	GuestAdditionsMode   string     `mapstructure:"guest_additions_mode"`
 	GuestAdditionsPath   string     `mapstructure:"guest_additions_path"`
 	GuestAdditionsURL    string     `mapstructure:"guest_additions_url"`
 	GuestAdditionsSHA256 string     `mapstructure:"guest_additions_sha256"`
@@ -87,6 +95,10 @@ func (b *Builder) Prepare(raws ...interface{}) error {
 		b.config.FloppyFiles = make([]string, 0)
 	}
 
+	if b.config.GuestAdditionsMode == "" {
+		b.config.GuestAdditionsMode = "upload"
+	}
+
 	if b.config.GuestAdditionsPath == "" {
 		b.config.GuestAdditionsPath = "VBoxGuestAdditions.iso"
 	}
@@ -145,6 +157,7 @@ func (b *Builder) Prepare(raws ...interface{}) error {
 
 	// Errors
 	templates := map[string]*string{
+		"guest_additions_mode":    &b.config.GuestAdditionsMode,
 		"guest_additions_sha256":  &b.config.GuestAdditionsSHA256,
 		"guest_os_type":           &b.config.GuestOSType,
 		"hard_drive_interface":    &b.config.HardDriveInterface,
@@ -264,6 +277,25 @@ func (b *Builder) Prepare(raws ...interface{}) error {
 		}
 	}
 
+	validMode := false
+	validModes := []string{
+		GuestAdditionsModeDisable,
+		GuestAdditionsModeAttach,
+		GuestAdditionsModeUpload,
+	}
+
+	for _, mode := range validModes {
+		if b.config.GuestAdditionsMode == mode {
+			validMode = true
+			break
+		}
+	}
+
+	if !validMode {
+		errs = packer.MultiErrorAppend(errs,
+			fmt.Errorf("guest_additions_mode is invalid. Must be one of: %v", validModes))
+	}
+
 	if b.config.GuestAdditionsSHA256 != "" {
 		b.config.GuestAdditionsSHA256 = strings.ToLower(b.config.GuestAdditionsSHA256)
 	}
diff --git a/builder/virtualbox/builder_test.go b/builder/virtualbox/builder_test.go
index 35ea79bf9..6a32d875f 100644
--- a/builder/virtualbox/builder_test.go
+++ b/builder/virtualbox/builder_test.go
@@ -65,6 +65,10 @@ func TestBuilderPrepare_Defaults(t *testing.T) {
 		t.Fatalf("should not have error: %s", err)
 	}
 
+	if b.config.GuestAdditionsMode != GuestAdditionsModeUpload {
+		t.Errorf("bad guest additions mode: %s", b.config.GuestAdditionsMode)
+	}
+
 	if b.config.GuestOSType != "Other" {
 		t.Errorf("bad guest OS type: %s", b.config.GuestOSType)
 	}
@@ -178,6 +182,38 @@ func TestBuilderPrepare_FloppyFiles(t *testing.T) {
 	}
 }
 
+func TestBuilderPrepare_GuestAdditionsMode(t *testing.T) {
+	var b Builder
+	config := testConfig()
+
+	// test default mode
+	delete(config, "guest_additions_mode")
+	err := b.Prepare(config)
+	if err != nil {
+		t.Fatalf("bad err: %s", err)
+	}
+
+	// Test another mode
+	config["guest_additions_mode"] = "attach"
+	b = Builder{}
+	err = b.Prepare(config)
+	if err != nil {
+		t.Fatalf("should not have error: %s", err)
+	}
+
+	if b.config.GuestAdditionsMode != GuestAdditionsModeAttach {
+		t.Fatalf("bad: %s", b.config.GuestAdditionsMode)
+	}
+
+	// Test bad mode
+	config["guest_additions_mode"] = "teleport"
+	b = Builder{}
+	err = b.Prepare(config)
+	if err == nil {
+		t.Fatal("should error")
+	}
+}
+
 func TestBuilderPrepare_GuestAdditionsPath(t *testing.T) {
 	var b Builder
 	config := testConfig()
diff --git a/builder/virtualbox/step_attach_guest_additions.go b/builder/virtualbox/step_attach_guest_additions.go
index 9bbeb949a..4ed259990 100644
--- a/builder/virtualbox/step_attach_guest_additions.go
+++ b/builder/virtualbox/step_attach_guest_additions.go
@@ -30,7 +30,7 @@ func (s *stepAttachGuestAdditions) Run(state multistep.StateBag) multistep.StepA
 	vmName := state.Get("vmName").(string)
 
 	// If we're not attaching the guest additions then just return
-	if !config.GuestAdditionsAttach {
+	if config.GuestAdditionsMode != GuestAdditionsModeAttach {
 		log.Println("Not attaching guest additions since we're uploading.")
 		return multistep.ActionContinue
 	}
diff --git a/builder/virtualbox/step_upload_guest_additions.go b/builder/virtualbox/step_upload_guest_additions.go
index ff2252c86..3999368a5 100644
--- a/builder/virtualbox/step_upload_guest_additions.go
+++ b/builder/virtualbox/step_upload_guest_additions.go
@@ -23,8 +23,8 @@ func (s *stepUploadGuestAdditions) Run(state multistep.StateBag) multistep.StepA
 	ui := state.Get("ui").(packer.Ui)
 
 	// If we're attaching then don't do this, since we attached.
-	if config.GuestAdditionsAttach {
-		log.Println("Not uploading guest additions since we're attaching.")
+	if config.GuestAdditionsMode != GuestAdditionsModeUpload {
+		log.Println("Not uploading guest additions since mode is not upload")
 		return multistep.ActionContinue
 	}