diff --git a/commands/mcndirs/utils.go b/commands/mcndirs/utils.go
index 6ed6b9ee01..6c660bba74 100644
--- a/commands/mcndirs/utils.go
+++ b/commands/mcndirs/utils.go
@@ -7,12 +7,15 @@ import (
 	"github.com/docker/machine/libmachine/mcnutils"
 )
 
+var (
+	BaseDir = os.Getenv("MACHINE_STORAGE_PATH")
+)
+
 func GetBaseDir() string {
-	baseDir := os.Getenv("MACHINE_STORAGE_PATH")
-	if baseDir == "" {
-		baseDir = filepath.Join(mcnutils.GetHomeDir(), ".docker", "machine")
+	if BaseDir == "" {
+		BaseDir = filepath.Join(mcnutils.GetHomeDir(), ".docker", "machine")
 	}
-	return baseDir
+	return BaseDir
 }
 
 func GetDockerDir() string {
diff --git a/commands/mcndirs/utils_test.go b/commands/mcndirs/utils_test.go
index 63fd6bada5..dbe08cca66 100644
--- a/commands/mcndirs/utils_test.go
+++ b/commands/mcndirs/utils_test.go
@@ -1,7 +1,6 @@
 package mcndirs
 
 import (
-	"os"
 	"path"
 	"strings"
 	"testing"
@@ -11,6 +10,8 @@ import (
 
 func TestGetBaseDir(t *testing.T) {
 	// reset any override env var
+	BaseDir = ""
+
 	homeDir := mcnutils.GetHomeDir()
 	baseDir := GetBaseDir()
 
@@ -21,13 +22,13 @@ func TestGetBaseDir(t *testing.T) {
 
 func TestGetCustomBaseDir(t *testing.T) {
 	root := "/tmp"
-	os.Setenv("MACHINE_STORAGE_PATH", root)
+	BaseDir = root
 	baseDir := GetBaseDir()
 
 	if strings.Index(baseDir, root) != 0 {
 		t.Fatalf("expected base dir with prefix %s; received %s", root, baseDir)
 	}
-	os.Setenv("MACHINE_STORAGE_PATH", "")
+	BaseDir = ""
 }
 
 func TestGetDockerDir(t *testing.T) {
@@ -41,7 +42,7 @@ func TestGetDockerDir(t *testing.T) {
 
 func TestGetMachineDir(t *testing.T) {
 	root := "/tmp"
-	os.Setenv("MACHINE_STORAGE_PATH", root)
+	BaseDir = root
 	machineDir := GetMachineDir()
 
 	if strings.Index(machineDir, root) != 0 {
@@ -55,12 +56,12 @@ func TestGetMachineDir(t *testing.T) {
 	if filename != "machines" {
 		t.Fatalf("expected machine dir \"machines\"; received %s", filename)
 	}
-	os.Setenv("MACHINE_STORAGE_PATH", "")
+	BaseDir = ""
 }
 
 func TestGetMachineCertDir(t *testing.T) {
 	root := "/tmp"
-	os.Setenv("MACHINE_STORAGE_PATH", root)
+	BaseDir = root
 	clientDir := GetMachineCertDir()
 
 	if strings.Index(clientDir, root) != 0 {
@@ -74,5 +75,5 @@ func TestGetMachineCertDir(t *testing.T) {
 	if filename != "certs" {
 		t.Fatalf("expected machine client dir \"certs\"; received %s", filename)
 	}
-	os.Setenv("MACHINE_STORAGE_PATH", "")
+	BaseDir = ""
 }
diff --git a/drivers/amazonec2/amazonec2_test.go b/drivers/amazonec2/amazonec2_test.go
index 7b615676c5..d243348706 100644
--- a/drivers/amazonec2/amazonec2_test.go
+++ b/drivers/amazonec2/amazonec2_test.go
@@ -5,6 +5,7 @@ import (
 	"os"
 	"testing"
 
+	"github.com/docker/machine/commands/mcndirs"
 	"github.com/docker/machine/drivers/amazonec2/amz"
 )
 
@@ -56,7 +57,7 @@ func getTestStorePath() (string, error) {
 	if err != nil {
 		return "", err
 	}
-	os.Setenv("MACHINE_STORAGE_PATH", tmpDir)
+	mcndirs.BaseDir = tmpDir
 	return tmpDir, nil
 }
 
diff --git a/drivers/softlayer/driver_test.go b/drivers/softlayer/driver_test.go
index 44688163e8..8875397662 100644
--- a/drivers/softlayer/driver_test.go
+++ b/drivers/softlayer/driver_test.go
@@ -5,6 +5,7 @@ import (
 	"os"
 	"testing"
 
+	"github.com/docker/machine/commands/mcndirs"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -56,7 +57,7 @@ func getTestStorePath() (string, error) {
 	if err != nil {
 		return "", err
 	}
-	os.Setenv("MACHINE_STORAGE_PATH", tmpDir)
+	mcndirs.BaseDir = tmpDir
 	return tmpDir, nil
 }
 
diff --git a/libmachine/cert/cert_test.go b/libmachine/cert/cert_test.go
index 69df4deed6..50dde8fd13 100644
--- a/libmachine/cert/cert_test.go
+++ b/libmachine/cert/cert_test.go
@@ -15,7 +15,6 @@ func TestGenerateCACertificate(t *testing.T) {
 	// cleanup
 	defer os.RemoveAll(tmpDir)
 
-	os.Setenv("MACHINE_DIR", tmpDir)
 	caCertPath := filepath.Join(tmpDir, "ca.pem")
 	caKeyPath := filepath.Join(tmpDir, "key.pem")
 	testOrg := "test-org"
@@ -30,7 +29,6 @@ func TestGenerateCACertificate(t *testing.T) {
 	if _, err := os.Stat(caKeyPath); err != nil {
 		t.Fatal(err)
 	}
-	os.Setenv("MACHINE_DIR", "")
 }
 
 func TestGenerateCert(t *testing.T) {
@@ -41,7 +39,6 @@ func TestGenerateCert(t *testing.T) {
 	// cleanup
 	defer os.RemoveAll(tmpDir)
 
-	os.Setenv("MACHINE_DIR", tmpDir)
 	caCertPath := filepath.Join(tmpDir, "ca.pem")
 	caKeyPath := filepath.Join(tmpDir, "key.pem")
 	certPath := filepath.Join(tmpDir, "cert.pem")
@@ -58,7 +55,6 @@ func TestGenerateCert(t *testing.T) {
 	if _, err := os.Stat(caKeyPath); err != nil {
 		t.Fatal(err)
 	}
-	os.Setenv("MACHINE_DIR", "")
 
 	if err := GenerateCert([]string{}, certPath, keyPath, caCertPath, caKeyPath, testOrg, bits); err != nil {
 		t.Fatal(err)
diff --git a/libmachine/host/migrate_v0_v1_test.go b/libmachine/host/migrate_v0_v1_test.go
index 199fb0eb57..c3131ebf55 100644
--- a/libmachine/host/migrate_v0_v1_test.go
+++ b/libmachine/host/migrate_v0_v1_test.go
@@ -1,17 +1,17 @@
 package host
 
 import (
-	"os"
 	"reflect"
 	"testing"
 
+	"github.com/docker/machine/commands/mcndirs"
 	"github.com/docker/machine/libmachine/auth"
 	"github.com/docker/machine/libmachine/engine"
 	"github.com/docker/machine/libmachine/swarm"
 )
 
 func TestMigrateHostV0ToV1(t *testing.T) {
-	os.Setenv("MACHINE_STORAGE_PATH", "/tmp/migration")
+	mcndirs.BaseDir = "/tmp/migration"
 	originalHost := &HostV0{
 		HostOptions:    nil,
 		SwarmDiscovery: "token://foobar",
diff --git a/libmachine/persist/filestore_test.go b/libmachine/persist/filestore_test.go
index e81918935d..67722ab714 100644
--- a/libmachine/persist/filestore_test.go
+++ b/libmachine/persist/filestore_test.go
@@ -8,6 +8,7 @@ import (
 	"path/filepath"
 	"testing"
 
+	"github.com/docker/machine/commands/mcndirs"
 	_ "github.com/docker/machine/drivers/none"
 	"github.com/docker/machine/libmachine/hosttest"
 )
@@ -23,7 +24,7 @@ func getTestStore() Filestore {
 		os.Exit(1)
 	}
 
-	os.Setenv("MACHINE_STORAGE_PATH", tmpDir)
+	mcndirs.BaseDir = tmpDir
 
 	return Filestore{
 		Path:             tmpDir,
diff --git a/main.go b/main.go
index fa3f123801..c43cff82d4 100644
--- a/main.go
+++ b/main.go
@@ -81,6 +81,7 @@ func main() {
 			ssh.SetDefaultClient(ssh.Native)
 		}
 		mcnutils.GithubApiToken = c.GlobalString("github-api-token")
+		mcndirs.BaseDir = c.GlobalString("storage-path")
 		return nil
 	}
 	app.Commands = commands.Commands
diff --git a/main_test.go b/main_test.go
new file mode 100644
index 0000000000..0287158a94
--- /dev/null
+++ b/main_test.go
@@ -0,0 +1,17 @@
+package main
+
+import (
+	"os"
+	"testing"
+
+	"github.com/docker/machine/commands/mcndirs"
+)
+
+func TestStorePathSetCorrectly(t *testing.T) {
+	mcndirs.BaseDir = ""
+	os.Args = []string{"docker-machine", "--storage-path", "/tmp/foo"}
+	main()
+	if mcndirs.BaseDir != "/tmp/foo" {
+		t.Fatal("Expected MACHINE_STORAGE_PATH environment variable to be /tmp/foo but was ", os.Getenv("MACHINE_STORAGE_PATH"))
+	}
+}