diff --git a/cmd/mattermost/commands/config.go b/cmd/mattermost/commands/config.go
index 39c12fc312..f74c25f323 100644
--- a/cmd/mattermost/commands/config.go
+++ b/cmd/mattermost/commands/config.go
@@ -261,6 +261,15 @@ func configSetCmdF(command *cobra.Command, args []string) error {
 	// update the config
 	app.UpdateConfig(f)
 
+	// Verify new config
+	if err := newConfig.IsValid(); err != nil {
+		return err
+	}
+
+	if err := utils.ValidateLocales(app.Config()); err != nil {
+		return errors.New("Invalid locale configuration")
+	}
+
 	// make the changes persist
 	app.PersistConfig()
 
diff --git a/cmd/mattermost/commands/config_test.go b/cmd/mattermost/commands/config_test.go
index f4514924e9..c949747341 100644
--- a/cmd/mattermost/commands/config_test.go
+++ b/cmd/mattermost/commands/config_test.go
@@ -109,6 +109,49 @@ func TestConfigGet(t *testing.T) {
 	assert.Contains(t, string(output), "ExportFromTimestamp")
 }
 
+func TestConfigSet(t *testing.T) {
+	dir, err := ioutil.TempDir("", "")
+	require.NoError(t, err)
+	defer os.RemoveAll(dir)
+
+	path := filepath.Join(dir, "config.json")
+	config := &model.Config{}
+	config.SetDefaults()
+	require.NoError(t, ioutil.WriteFile(path, []byte(config.ToJson()), 0600))
+
+	// Error when no arguments are given
+	assert.Error(t, RunCommand(t, "--config", path, "config", "set"))
+
+	// Error when only one argument is given
+	assert.Error(t, RunCommand(t, "--config", path, "config", "set", "test"))
+
+	// Error when the wrong key is set
+	assert.Error(t, RunCommand(t, "--config", path, "config", "set", "invalid-key", "value"))
+	assert.Error(t, RunCommand(t, "--config", path, "config", "get", "invalid-key"))
+
+	// Error when the wrong value is set
+	assert.Error(t, RunCommand(t, "--config", path, "config", "set", "EmailSettings.ConnectionSecurity", "invalid"))
+	output := CheckCommand(t, "--config", path, "config", "get", "EmailSettings.ConnectionSecurity")
+	assert.NotContains(t, string(output), "invalid")
+
+	// Error when the wrong locale is set
+	assert.NoError(t, RunCommand(t, "--config", path, "config", "set", "LocalizationSettings.DefaultServerLocale", "es"))
+	assert.Error(t, RunCommand(t, "--config", path, "config", "set", "LocalizationSettings.DefaultServerLocale", "invalid"))
+	output = CheckCommand(t, "--config", path, "config", "get", "LocalizationSettings.DefaultServerLocale")
+	assert.NotContains(t, string(output), "invalid")
+	assert.NotContains(t, string(output), "\"en\"")
+
+	// Success when a valid value is set
+	assert.NoError(t, RunCommand(t, "--config", path, "config", "set", "EmailSettings.ConnectionSecurity", "TLS"))
+	output = CheckCommand(t, "--config", path, "config", "get", "EmailSettings.ConnectionSecurity")
+	assert.Contains(t, string(output), "TLS")
+
+	// Success when a valid locale is set
+	assert.NoError(t, RunCommand(t, "--config", path, "config", "set", "LocalizationSettings.DefaultServerLocale", "es"))
+	output = CheckCommand(t, "--config", path, "config", "get", "LocalizationSettings.DefaultServerLocale")
+	assert.Contains(t, string(output), "\"es\"")
+}
+
 func TestStructToMap(t *testing.T) {
 
 	cases := []struct {